- Propargylation of CoQ0 through the Redox Chain Reaction
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An efficient catalytic propargylation of CoQ0 is described by employing the cooperative effect of Sc(OTf)3 and Hantzsch ester. It is suggested to work through the redox chain reaction, which involves hydroquinone and dimeric propargylic moiety intermediates. A broad range of propargylic alcohols can be converted into the appropriate derivatives of CoQ0 containing triple bonds in good to excellent yields. The mechanism of the given transformation is also discussed.
- Mlynarski, Jacek,Pawlowski, Robert,Stodulski, MacIej
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- Multisubstituted pyrazole synthesis via [3?+?2] cycloaddition/rearrangement/N[sbnd]H insertion cascade reaction of α-diazoesters and ynones
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The cascade reactions of alkyl α-diazoesters and ynones using Al(OTf)3 as the catalyst are described. A series of 4-substituted pyrazoles were obtained via [3 + 2] cycloaddition, 1,5-ester shift, 1,3-H shift, and N[sbnd]H insertion process. Deuterium labelling experiments, kinetic studies and control experiments were carried out for the rationalization of the mechanism.
- Feng, Xiaoming,Liu, Xiaohua,Zeng, Zi,Zhao, Peng
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supporting information
p. 132 - 135
(2020/12/21)
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- Regioselective Synthesis of Multifunctional Allylic Amines; Access to Ambiphilic Aziridine Scaffolds
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We describe, for the first time, a highly regioselective hydrosilylation of propargylic amines. The reaction utilizes a PtCl2/XantPhos catalyst system to deliver hydrosilanes across the alkyne to afford multifunctional allylic amines in high yields. The reaction is tolerant to a wide variety of functional groups and provides high value intermediates with two distinct functional handles. The synthetic applicability of the reaction has been shown through the synthesis of diverse ambiphilic aziridines.
- McLaughlin, Mark G.,Roberts, Dean D.
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supporting information
p. 4463 - 4467
(2021/06/28)
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- New α-Hydroxy-1,2,3-triazoles and 9H-Fluorenes-1,2,3-triazoles: H Synthesis and Evaluation as Glycine Transporter 1 Inhibitors
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Two series of new compounds containing 1,2,3-triazole moiety were designed as putative GlyT1 inhibitors aiming the discovery of new hits with activity in cognitive disorders. 1,4-Disubstituted α-hydroxy-1,2,3-triazoles were obtained as racemates in moderate to good yields by the copper-catalyzed azide-alkyne cycloaddition (CuAAC) reaction (click chemistry) as the key step between propargyl alcohols and aryl azides, previously prepared from anilines or boronic acids. Benzo[c]chromene-triazoles were planned to be obtained by palladium-catalyzed C?H activation using [bis(trifluoroacetoxy)iodobenzene] (PhI(TFA)2) of some α-hydroxy-1,2,3-triazoles, since benzo[c]chromenes are also privileged groups with several biological activities, including to the central nervous system. Unexpectedly, 9H-fluorenes-1,2,3-triazoles, instead of benzo[c]chromenetriazoles, were obtained by Friedel-Crafts alkylation reaction. The two series of compounds were tested for inhibition of the glycine transporter (rat GlyT1 isoform) but only the α-hydroxy-1,2,3-triazole 9b was active (half maximal inhibitory concentration (IC50) = 8.0 μM).
- Buarque, Camilla D.,Guimar?es, Marilia Z.,López?Corcuera, Beatriz,Neto, Jo?o Gon?alves,No?l, Fran?ois,Silva, Rafaela R.,da Silva, Veronica D.
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p. 1258 - 1269
(2020/10/14)
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- Gold-Catalyzed Iminations of Terminal Propargyl Alcohols with Anthranils with Atypical Chemoselectivity for C(1)-Additions and 1,2-Carbon Migration
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This work reports gold-catalyzed iminations of terminal propargyl alcohols with anthranils or isoxazoles to yield E-configured α-amino-2-en-1-ones and -1-als with complete chemoselectivity. These catalytic iminations occur exclusively with C(1)-nucleophilic additions on terminal alkynes, in contrast to a typical C(2)-route. For 3,3-dialkylprop-1-yn-3-ols, a methyl substituent is superior to long alkyl chains as the 1,2-migration groups toward α-imino gold carbenes. For secondary prop-1-yn-3-ols, phenyl, vinyl, and cyclopropyl substituents are better than hydrogen as the migrating groups, obviating typical gold carbene reactions. DFT calculations have been performed to rationalize the observed C(1)-regioselectivity and the preferable cyclopropyl migration based on gold carbene pathways.
- Skaria, Manisha,More, Sayaji Arjun,Kuo, Tung-Chun,Cheng, Mu-Jeng,Liu, Rai-Shung
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supporting information
p. 3600 - 3608
(2020/03/04)
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- A Domino Strategy for the Synthesis of 2H-Pyrans from Propargyl Vinyl Ethers
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Stable monocyclic 2H-pyrans are synthesized from readily available tertiary propargyl vinyl ethers via a metal-free all-pericyclic domino manifold involving a sequential propargyl Claisen rearrangement/[1,3]H-shift/oxa-6π electrocyclization set of reactions. The wide scope of this protocol is exemplified by the synthesis of 21 different 2H-pyrans incorporating a varied substitution pattern at the ring.
- Tejedor, David,Delgado-Hernández, Samuel,Diana-Rivero, Raquel,Díaz-Díaz, Abián,García-Tellado, Fernando
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p. 1784 - 1790
(2019/02/19)
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- Metal-free synthesis of activated ynesulfonamides and tertiary enesulfonamides
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An operationally simple synthesis of activated ynesulfonamides and enesulfonamides is described. Ynesulfonamides can be obtained through reaction of sulfonylamides with activated bromoalkynes and Triton B in a short time at room temperature. Likewise, terminal alkynes react with sulfonylamides to provide enesulfonamides. Z/E enesulfonamides can be transformed exclusively into E enesulfonamides.
- Andna, Lucile,Miesch, Laurence
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supporting information
p. 5688 - 5692
(2019/06/19)
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- Access to Enantioenriched Organosilanes from Enals and β-Silyl Enones: Carbene Organocatalysis
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Herein, an efficient route to enantioenriched organosilanes, containing two consecutive stereogenic centers, from enals and β-silyl enones under carbene organocatalysis is described. Under mild reaction conditions, this transition-metal-free strategy exhibits a broad substrate scope, and excellent diastereo- and enantioselectivity.
- Zhang, Yuxia,Huang, Jie,Guo, Yingying,Li, Lin,Fu, Zhenqian,Huang, Wei
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supporting information
p. 4594 - 4598
(2018/03/21)
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- Cascade and Effective Syntheses of Functionalized Tellurophenes
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A one-pot and transition-metal-catalyst-free synthetic strategy to construct functionalized tellurophenes has been developed. Substituted 1,1-dibromo-1-en-3-ynes are smoothly converted to tellurophenes with telluride salts in high yield via a series of cascade reactions through reductive debromination, hydrotelluration, nucleophilic cyclization, and aromatization. Close inspection of the results clearly showed that the reactivity of in situ prepared telluride salts are significantly influenced by the polarity of the solvent system and the electronic nature of the substituent on the enyne substrate. This method reports the first direct synthesis of 3-aryltellurophenes in high yields at room temperature. This novel reaction strategy is also found to be a promising synthetic method for multisubstituted tellurophenes and selenophenes.
- Karapala, Vamsi Krishna,Shih, Hong-Pin,Han, Chien-Chung
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supporting information
p. 1550 - 1554
(2018/03/23)
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- Gold(I)-Catalyzed Tandem Cycloisomerization and Fluorination of 1,3(4)-Enyne Esters with NFSI: One-Pot Assembly of 5-Fluoro- Cyclopentenones
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An efficient synthetic approach for the synthesis of 5-fluoro-cyclopentenones containing a fluorine-substituted carbon stereocenter that relies on gold(I)-catalyzed cycloisomerization and fluorination sequence of 1,3(4)-enyne esters with N-fluorbenzensulfonimide (NFSI) is described. This tandem transformation exhibited a broad substrate scope and excellent functional group compatibility, providing a novel protocol for rapid assembly 5-fluoro-cyclopentenones in good to excellent yields under mild reaction conditions. The mechanistic studies revealed that the transformation involves a gold-catalyzed cycloisomerization and electrophilic fluorination cascade to give the 5-fluoro-cyclopentenones. (Figure presented.).
- Chen, Xianxiao,Zhou, Yuanyuan,Hong, Mei,Ling, Yuan,Yin, Dongliang,Wang, Shifa,Zhang, Xiaoxiang,Rao, Weidong
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supporting information
p. 3700 - 3708
(2018/09/12)
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- Highly Efficient Synthesis of Multi-Substituted Allenes from Propargyl Acetates and Organoaluminum Reagents Mediated by Palladium
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A simple and mild catalytic S N 2′ substitution reaction of propargyl acetates with organoaluminum reagents is reported. The S N 2′ substitution reaction of propargyl acetates with organoaluminum reagents mediated by Pd(PhP 3) 2 Cl 2 (1 mol%)/PPh 3 (2 mol%)/K 2 CO 3 in tetrahydrofuran at 60 °C for 3-4 hours afforded the corresponding multi-substituted allenes in good yields (up to 94%) with high selectivities (up to 99%). The process was simple and easily performed, which offers an efficient method to synthesize the multi-substituted allene derivatives.
- Zhang, Zhen,Shao, Xuebei,Zhang, Gang,Li, Qinghan,Li, Xinying
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p. 3643 - 3653
(2017/08/16)
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- Direct spirocyclization from keto-sulfonamides: An approach to azaspiro compounds
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Spontaneous spirocyclization of keto-sulfonamides via ynamides through a one-pot process is presented. Push-pull ynamides were obtained through Michael addition/elimination without Cu. The obtained azaspiro compounds are building blocks for indole alkaloids. Theoretical studies provide insights into the mechanism of the formal Conia-ene reaction.
- Beltran, Frédéric,Fabre, Indira,Ciofini, Ilaria,Miesch, Laurence
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supporting information
p. 5042 - 5045
(2017/11/06)
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- An Unexpected Domino Reaction of β-Keto Sulfones with Acetylene Ketones Promoted by Base: Facile Synthesis of 3(2H)-Furanones and Sulfonylbenzenes
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An unexpected domino reaction of β-keto sulfones with acetylene ketones has been developed. The domino reaction of β-keto sulfones with diynones proceeded smoothly in the presence of 30 mol% K2CO3 without other additives, and afforded the novel 3(2H)-furanone derivatives. On replacing the diynones with terminal alkyne ketones, the reaction regioselectivity was changed and sulfonylbenzenes were obtained via benzannulation in good yields. (Figure presented.).
- Tong, Wei,Li, Qian-Yu,Xu, Yan-Li,Wang, Heng-Shan,Chen, Yan-Yan,Pan, Ying-Ming
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supporting information
p. 4025 - 4035
(2017/11/21)
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- Gold-Catalyzed Dehydrogenative Cycloisomerization of 1,4-Enyne Esters to 3,5-Disubstituted Phenol Derivatives
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A method to prepare synthetically important 3,5-disubstituted phenol derivatives that relies on the sequential gold(I)-catalyzed dehydrogenative cycloisomerization of 1,4-enyne esters in the presence of 2,3-dichloro-5,6-dicyanobenzoquinone (DDQ) or N-fluorobenzenesulfonimide (NFSI) is described. The synthetic versatility of the methodology was exemplified by a gram-scale reaction of one example, the ease to realize subsequent functional transformations of an adduct, and the application of the method to the synthesis of the bioactive molecule LUF5771. (Figure presented.).
- Chen, Cuili,Chen, Xianxiao,Zhang, Xiaoxiang,Wang, Shifa,Rao, Weidong,Chan, Philip Wai Hong
-
supporting information
p. 4359 - 4368
(2017/12/26)
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- Silver(I)-Catalyzed Addition of Phenols to Alkyne Cobalt Cluster Stabilized Carbocations
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A smooth catalytic method to use phenols as the nucleophilic partner in the Nicholas reaction has been developed. The method uses either AgIor AuIcatalysts with AgClO4or AgBF4as the most efficient catalysts tested. Neither additional additives nor cocatalysts were required and the formation of the corresponding phenol adducts occurred in excellent yields. The process has the single limitation of the inability of less nucleophilic phenols (4-nitrophenol) to generate the corresponding adducts. Additionally, the reaction is highly diastereoselective. DFT calculations allow a catalytic cycle to be proposed that involves trimetallic intermediates; the rate-determining step of the reaction is hydroxy-group elimination in a cobalt–silver trimetallic intermediate.
- Valderas, Carolina,Casarrubios, Luis,Lledos, Agusti,Ortu?o, Manuel A.,de la Torre, María C.,Sierra, Miguel A.
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supporting information
p. 9015 - 9023
(2016/07/06)
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- Silaborative Carbocyclizations of 1,7-Enynes. Diastereoselective Preparation of Chromane Derivatives
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Palladium(0)-catalyzed carbocyclization of 1,7-enynes mediated by (chlorodimethylsilyl)pinacolborane proceeds with 1,8-addition of the silicon and boron functions to give functionalized cyclohexane derivatives with boron attached to the exocyclic olefin. A variety of chromane dervatives are accessible by this method. In contrast to the analogous reactions with 1,6-enynes, the configuration of the newly formed stereogenic center is controlled by a stereogenic center present in the substrate.
- Xiao, You-Cai,Moberg, Christina
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supporting information
p. 308 - 311
(2016/02/03)
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- : NBu4NPF6 promoted regioselective cascade synthesis of functionally embellished naphthofurans under acid, metal & solvent free conditions
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nBu4NPF6 mediated highly regioselective synthesis of functionally embellished naphthofurans has been achieved from easily available naphthols and propargyl alcohols through a cascade benzylation, oxacyclisation (5-exo dig) and isomerization under solvent free conditions. The reaction works in a short time through dibenzyl ether formation followed by the decomposition to the carbocation to furnish the high yielding products with large substrate scope. The synthetic utility of the products is demonstrated through C(sp3)-H functionalization. In addition, we investigated selected naphthofurans for their anti-amyloidogenic properties. Preliminary studies suggest that these are excellent inhibitors for amyloid formation, a hallmark for several neurodegenerative diseases.
- Pareek, Abhishek,Dada, Ravikrishna,Rana, Monika,Sharma, Anuj K.,Yaragorla, Srinivasarao
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p. 89732 - 89743
(2016/10/03)
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- One-Pot Cannizzaro Cascade Synthesis of ortho-Fused Cycloocta-2,5-dien-1-ones from 2-Bromo(hetero)aryl Aldehydes
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An intramolecular Cannizzaro-type hydride transfer to an in situ prepared allene enables the synthesis of ortho-fused 4-substituted cycloocta-2,5-dien-1-ones with unprecedented technical ease for an eight-ring carboannulation. Various derivatives could be obtained from commercially available (hetero)aryl aldehydes, trimethylsilylacetylene, and simple propargyl chlorides in good yields. A cascade process that is triggered by an intramolecular Cannizzaro-type hydride transfer to an in situ prepared allene leads to the formation of 4-substituted cycloocta-2,5-dien-1-ones. Various derivatives could be obtained from commercially available (hetero)aryl aldehydes, trimethylsilylacetylene, and simple propargyl chlorides in good yields.
- Burroughs, Laurence,Eccleshare, Lee,Ritchie, John,Kulkarni, Omkar,Lygo, Barry,Woodward, Simon,Lewis, William
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p. 10648 - 10651
(2015/09/02)
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- Copper(II)-Catalyzed [4+1] annulation of propargylamines with N,O-acetals: Entry to the synthesis of polysubstituted pyrrole derivatives
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Described herein is the CuCl2-catalyzed [4+1] annulation of a variety of propargylamines with N,O-acetals that function as a C1 unit, leading to the production of polysubstituted pyrrole derivatives. Three important features of the N,O-acetal during the [4+1] annulation series via 5-endo-dig cyclization are described: an enolizable substituent adjacent to the central sp3-carbon is required, the central sp3-carbon displays the functions of both an electrophile and a nucleophile, and liberation of the secondary amine smoothly leads to the aromatization. A CuCl2-catalyzed [4+1] annulation of propargylamines with N,O-acetals having an ester, a ketone, and an amide moiety, leading to the facile preparation of polysubstituted pyrrole derivatives is presented. This annulation series was achieved through 5-endo-dig cyclization and subsequent aromatization in one pot.
- Sakai, Norio,Hori, Hiroaki,Ogiwara, Yohei
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supporting information
p. 1905 - 1909
(2015/03/18)
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- Benzannulation of triynes to generate functionalized arenes by spontaneous incorporation of nucleophiles
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The thermal reaction of ester-tethered 1,3,8-triynes provides novel benzannulation products with concomitant incorporation of a nucleophile. Evidence suggests that this reaction proceeds via an allene-enyne intermediate generated by an Alder-ene reaction in the first step. Depending on the substituent of the alkyne moiety on the allene-enyne intermediate, the subsequent transformation can take one of two different paths, each leading to discrete aromatization products. The benzannulation of a silane-substituted 1,3,8-triynes provides arene products with a nucleophile incorporated onto the newly formed benzene core, whereas an aryl substituent leads to nucleophile trapping at the benzylic carbon atom connected to the aryl substituent. The formation of these two different products results from the involvement of two regioisomeric allene-enyne intermediates.
- Karmakar, Rajdip,Yun, Sang Young,Chen, Jiajia,Xia, Yuanzhi,Lee, Daesung
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supporting information
p. 6582 - 6586
(2015/06/02)
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- Trialkyl Methanetricarboxylate as Dialkyl Malonate Surrogate in Copper-Catalyzed Enantioselective Propargylic Substitution
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The first copper-catalyzed enantioselective propargylation of trialkyl methantricarboxylate with propargylic alcohol derivatives was developed. The tricarboxylate unit in the obtained adducts could be easily transformed into a malonate moiety by treating with in situ generated NaOEt in excellent yield without racemization.
- Huang, Guanxin,Cheng, Cang,Ge, Luo,Guo, Beibei,Zhao, Long,Wu, Xiaoyu
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supporting information
p. 4894 - 4897
(2015/10/12)
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- SOLUTION PHASE POLYDIACETYLENE SYNTHESIS BY ALKYNE METATHESIS
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The present disclosure provides compositions for alkyne metathesis catalysts and methods for preparing enediynes and alkyne metathesis catalysts. The disclosure also provides methods for catalyzing alkyne metathesis reactions and polymerization of enediyne substrates to polydiacetylenes in solution-phase.
- -
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Paragraph 0032
(2014/02/16)
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- Catalytic asymmetric enyne addition to aldehdyes and Rh(I)-catalyzed stereoselective domino Pauson-Khand/[4 + 2] cycloaddition
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The 1,1′-bi-2-naphthol-ZnEt2-Ti(OiPr) 4-Cy2NH system is found to catalyze the 1,3-enyne addition to aliphatic aldehydes as well as other aldehydes at room temperature with 75-96% yield and 82-97% ee. This system is also broadly applicable for the highly enantioselective reaction of other alkyl-, aryl-, and silylalkynes with structurally diverse aldehydes. The propargylic alcohols prepared from the catalytic asymmetric enyne addition to aliphatic aldehydes are used to prepare a series of optically active trienynes. In the presence of a catalytic amount of [RhCl(CO)2]2 and 1 atm of CO, the optically active trienynes undergo highly stereoselective domino Pauson-Khand/[4 + 2] cycloaddition to generate optically active multicyclic products. The Rh(I) catalyst is also found to catalyze the coupling of a diyne with CO followed by [4 + 2] cycloaddition to generate an optically active multicyclic product. These transformations are potentially useful for the asymmetric synthesis of polyquinanes containing a quaternary chiral carbon center.
- Chen, Wei,Tay, Jia-Hui,Ying, Jun,Yu, Xiao-Qi,Pu, Lin
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p. 2256 - 2265
(2013/04/24)
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- Au-catalyzed formation of functionalized quinolines from 2-alkynyl arylazide derivatives
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A new method for converting 2-alkynyl arylazide derivatives into functionalized polysubstituted quinolines following a gold-catalyzed 1,3-acetoxy shift/cyclization/1,2-group shift sequence has been developed. This transformation proceeds under mild reaction conditions, is efficient, and tolerates a large variety of functional groups.
- Gronnier, Colombe,Boissonnat, Guillaume,Gagosz, Fabien
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supporting information
p. 4234 - 4237
(2013/09/12)
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- Silver(I)-catalyzed reaction between pyrazole and propargyl acetates: Stereoselective synthesis of the scorpionate ligands (E)-allyl-gem-dipyrazoles (ADPs)
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The reaction between readily accessible pyrazole and propargyl acetates in the presence of Ag(I) catalyst yielded a new class of (E)-allyl-gem-dipyrazole scorpionate ligands: 1-aryl-2-N-pyrazolyl allyl acetates and 1,3-dipyrazolyl-3-arylpropene. The reaction showed broad substrate scope, and various functional and protecting groups were tolerated under the reaction conditions. The palladium(II) scorpionate complex could thus be easily prepared and successfully employed in Suzuki-Miyaura cross-couplings in water.
- Bhanuchandra,Kuram, Malleswara Rao,Sahoo, Akhila K.
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p. 11824 - 11834
(2014/01/06)
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- Lithiation of 1,2-dichloroethene in flow microreactors: Versatile synthesis of alkenes and alkynes by precise residence-time control
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It′s all about the timing: Precise control of the residence time (tRx; see picture) of reactive intermediates in flow microreactors enables the reaction pathway of lithiated 1,2-dichloroethene to be switched to produce either alkenes or alkynes. This method also allows versatile syntheses of asymmetric disubstituted dichloroalkenes and alkynes. Copyright
- Nagaki, Aiichiro,Matsuo, Chika,Kim, Songhee,Saito, Kodai,Miyazaki, Atsuo,Yoshida, Jun-Ichi
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supporting information; experimental part
p. 3245 - 3248
(2012/05/31)
-
- Novel sequential 1,4-Brook rearrangement-Wittig reaction: New one-pot approach for silyl dienol ethers
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A novel one-pot synthetic method of silyl dienol ethers via 1,4-Brook rearrangement-Wittig reaction sequence has been developed. This tandem reaction proceeded via the intramolecular silyl migration step, which enabled stereoselective formation of phosphorane intermediates. The reaction is operationally simple and high yielding, thus providing a new useful formula for silyl dienol ether synthesis.
- Matsuya, Yuji,Koiwai, Azusa,Minato, Daishiro,Sugimoto, Kenji,Toyooka, Naoki
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supporting information
p. 5955 - 5957,3
(2020/07/31)
-
- Synthesis of allenes via gold-catalyzed intermolecular reaction of propargylic alcohols and aromatic compounds
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Functionalized allenes are efficiently synthesized in moderate to high yield from gold-catalyzed intermolecular reaction of propargylic alcohols and aromatic compounds. The user-friendly process could be conducted under mild reaction conditions with easily accessible starting materials.
- Xu, Cheng-Fu,Xu, Mei,Yang, Liu-Qing,Li, Chuan-Ying
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experimental part
p. 3010 - 3016
(2012/05/05)
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- Rhodium-catalyzed intra- and intermolecular [5 + 2] cycloaddition of 3-acyloxy-1,4-enyne and alkyne with concomitant 1,2-acyloxy migration
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A new type of rhodium-catalyzed [5 + 2] cycloaddition was developed for the synthesis of seven-membered rings with diverse functionalities. The ring formation was accompanied by a 1,2-acyloxy migration event. The five- and two-carbon components of the cycloaddition are 3-acyloxy-1,4-enynes (ACEs) and alkynes, respectively. Cationic rhodium(I) catalysts worked most efficiently for the intramolecular cycloaddition, while only neutral rhodium(I) complexes could facilitate the intermolecular reaction. In both cases, electron-poor phosphite or phosphine ligands often improved the efficiency of the cycloadditions. The scope of ACEs and alkynes was investigated in both the intra- and intermolecular reactions. The resulting seven-membered-ring products have three double bonds that could be selectively functionalized.
- Shu, Xing-Zhong,Li, Xiaoxun,Shu, Dongxu,Huang, Suyu,Schienebeck, Casi M.,Zhou, Xin,Robichaux, Patrick J.,Tang, Weiping
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supporting information; experimental part
p. 5211 - 5221
(2012/05/05)
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- A convenient approach to β-heteroarylated (C-N bond) ketones from Cs2CO3 promoted reaction between propargyl alcohols and nitrogen-heterocycles
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An efficient and direct approach to β-heteroarylated (C-N bond) ketones is demonstrated. Base promoted redox isomerization of propargyl alcohol to α,β-unsaturated ketone followed by conjugate addition to NH-heteroarenes affords a wide range of β-heteroarylated ketones in good to excellent yields. Aryl, heteroaryl, alkyl C(sp), and terminal alkynes containing unactivated propargyl alcohols effectively undergo redox-isomerization conjugate addition (RICA) with NH-heteroarenes. Reaction of 3-substituted pyrazoles or indazole with propargyl alcohols enables highly regioselective products. A diverse range of NH-bearing nucleophiles such as: pyrazoles, imidazole, triazoles, pyrrole, indoles and aniline participate in this reaction and deliver the corresponding β-heteroarylated ketones.
- Bhanuchandra,Kuram, Malleswara Rao,Sahoo, Akhila K.
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experimental part
p. 3538 - 3555
(2012/05/20)
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- Palladacycle-catalyzed reaction of bicyclic alkenes with terminal ynones: Regiospecific synthesis of polysubstituted furans
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A new synthetic strategy to access polysubstituted furans regiospecifically has been developed using simple bicyclic alkenes and terminal ynones as starting materials with palladacycles as unique active catalysts. A rational mechanism has also been proposed. This reaction features mild reaction conditions, easily available starting materials and palladacycle catalysts, a wide substrate scope, and high regiospecificity.
- Ge, Guang-Cun,Mo, Dong-Liang,Ding, Chang-Hua,Dai, Li-Xin,Hou, Xue-Long
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supporting information
p. 5756 - 5759
(2013/01/15)
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- A new and general one-pot synthesis of propargyl alcohols from esters
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Intermediates easily prepared by partial reduction of various esters with LDBBA as a reducing agent smoothly react with lithium acetylides to give propargyl alcohols, without isolation of partial reduction intermediates, in good yields (73-83%).
- Chae, Min Jung,Jeon, Ah Ram,Livinghouse, Tom,An, Duk Keun
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experimental part
p. 3281 - 3283
(2011/05/05)
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- Base-catalyzed cascade 1,3-H shift/cyclization reaction to construct polyaromatic furans
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A convenient new method was developed to prepare unfused polyaromatic furan derivatives from diynyl-1,6-diols through a novel base-catalyzed cascade 1,3-H shift/cyclization process. Deuterium experiments were performed to determine that the 1,3-H shift was the rate-determining step. Copyright
- Wang, Ya-Hui,Liu, Heng,Zhu, Li-Li,Li, Xiao-Xiao,Chen, Zili
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supporting information; experimental part
p. 707 - 712
(2011/05/06)
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- Gold-catalyzed regioselective hydration of propargyl acetates assisted by a neighboring carbonyl group: Access to α-acyloxy methyl ketones and synthesis of (±)-actinopolymorphol B
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A general atom-economical approach for the synthesis of α-acyloxy methyl ketone is demonstrated through regioselective hydration of a wide range of propargyl acetates. Readily available catalyst comprising of 1% Ph 3PAuCl and 1% AgSbF6 in dioxane-H2O efficiently hydrolyzes the terminal alkynes of the propargyl acetate in the absence of acid promoters at ambient temperature within a short time. Effective regioselective hydration is facilitated by the neighboring carbonyl group as demonstrated through 18O-labeling study. Compatibility of functional moieties and tolerance to various acid-labile protecting groups are observed. The catalytic condition is also suitable to perform hydration of TMS-substituted propargyl acetates, even though it requires prolonged reaction time for completion. Stereointegrity of the propargylic acetate is preserved during the hydration. The robustness of the system is successfully demonstrated through gram scale preparation of the product in nearly quantitative yield. The common α-acyloxy methyl ketone is transformed to 1,2-diol and 1,2-amino alcohol derivatives. Synthesis of actinopolymorphol B is achieved for the first time involving hydration of the propargyl acetate as the key step.
- Ghosh, Nayan,Nayak, Sanatan,Sahoo, Akhila K.
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supporting information; experimental part
p. 500 - 511
(2011/04/17)
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- Highly enantioselective addition of trimethylsilylacetylene to aldehydes catalyzed by a zinc-amino-alcohol complex
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A fine addition! A highly enantioselective and efficient procedure for the amino-alcohol-zinc-catalyzed addition of trimethylsilylacetylene to aromatic, α,β-unsaturated, and aliphatic aldehydes has been developed (see scheme; R=aryl, alkynyl, or alkyl; TMS=trimethylsilyl; TBDMS=tert- butyldimethylsilyl). The present protocol was successfully applied in the concise synthesis of the natural products marine alkynol and falcarindiol. Copyright
- Li, Zhi-Yuan,Wang, Min,Bian, Qing-Hua,Zheng, Bing,Mao, Jian-You,Li, Shuo-Ning,Liu, Shang-Zhong,Wang, Ming-An,Zhong, Jiang-Chun,Guo, Hong-Chao
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supporting information; experimental part
p. 5782 - 5786
(2011/06/26)
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- The catalytic asymmetric 1,3-dipolar cycloaddition of ynones with azomethine ylides
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The first catalytic asymmetric 1,3-dipolar cycloaddition of electron-deficient carbon-carbon triple bonds with azomethine ylides has been established. This reaction provides an unprecedented approach to access novel 2,5-dihydropyrrole derivatives with potential bioactivities in perfect enantioselectivities of up to >99% ee.
- Shi, Feng,Luo, Shi-Wei,Tao, Zhong-Lin,He, Long,Yu, Jie,Tu, Shu-Jiang,Gong, Liu-Zhu
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supporting information; experimental part
p. 4680 - 4683
(2011/11/06)
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- Iron-catalyzed C-O bond activation for the synthesis of propargyl-1,2,3-triazoles and 1,1-bis-triazoles
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(Equation Presented). The FeCl3-catalyzed triazole propargylation was developed. This transformation was suitable for a large scope of substituted propargyl alcohols, giving the corresponding propargyl triazoles in excellent yields (up to 96%). Further derivatization produced the 1,1-bis-triazoles in excellent yields and regioselectivity, which could be applied as potential transition metal ligands or new reagents.
- Yan, Wuming,Wang, Qiaoyi,Chen, Yunfeng,Petersen, Jeffrey L.,Shi, Xiaodong
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supporting information; experimental part
p. 3308 - 3311
(2010/10/19)
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- Gold-catalyzed synthesis of bicyclo[3.2.0]heptenes via a formal [3+2]/[2+2]-annulation of allylsilane with 4-methoxybut-2-yn1-ols
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This work reports the novel gold-catalyzed [3+ 2]/[2+2]-annulation of allylsilane with Amethoxybut-2-yn-l-ols that yields highly strained bicyclo[3.2.0]heptene products efficiently and stereoselectively.
- Yang, Chun-Yao,Wang, Chiou-Dong,Tian, Shu-Fan,Liu, Rai-Shung
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supporting information; experimental part
p. 1605 - 1609
(2010/09/05)
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- Chemoselective addition of in situ prepared lithium alkynyl borates to aldehydes: a practical and transition metal free approach toward the synthesis of propargylic alcohols
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A convenient synthesis of functionalized propargylic alcohols arising from the 1,2-addition of lithium alkynyl-trimethyl borate onto aldehydes under transition metal free mild conditions is reported. The reaction tolerates a wide range of functional groups, is highly chemoselective and the propargylic alcohols are isolated in good to excellent yields.
- Francesco, Irene Notar,Renier, Antoine,Wagner, Alain,Colobert, Fran?oise
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experimental part
p. 1386 - 1389
(2010/04/25)
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- Gold-catalyzed ethynylation of arenes
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(Figure Presented) A novel gold-catalyzed ethynylation of aromatic rings with electron-deficient alkynes via gold catalyzed C-H activation of both C sp-H and Csp2-H bonds has been developed. This transformation provides aromatic propiolates difficult to prepare by other methods, highlighting the synthetic potential of gold chemistry.
- De Haro, Teresa,Nevado, Cristina
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supporting information; experimental part
p. 1512 - 1513
(2010/04/04)
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- Gold-catalyzed one-step practical synthesis of oxetan-3-ones from readily available propargylic alcohols
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A general solution for the synthesis of various oxetan-3-ones is developed. This reaction uses readily available propargylic alcohols as substrates and proceeds without the exclusion of moisture or air ("open flask"). Notably, oxetan-3-one, a highly valuable substrate for drug discovery, can be prepared in one step from propargyl alcohol in a fairly good yield. The facile formation of the strained oxetane ring provides strong support for the intermediacy of α-oxo gold carbenes. This safe and efficient generation of gold carbenes via intermolecular alkyne oxidation offers a potentially general entry into α-oxo metal carbene chemistry without using hazardous diazo ketones.
- Ye, Longwu,He, Weimin,Zhang, Liming
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supporting information; experimental part
p. 8550 - 8551
(2010/08/06)
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- Preparation of some heterocyclic enones and ynones by isomerisation of the propargylic alcohols
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The propargylic alcohols were synthesised by treatment of aldehydes with substituted acetylenes. The conversion of propargylic alcohols to propynones and propenones takes place with pyridine hydrochloride in methanol at room temperature. In presence of pyridinium triflate and p-toluenesulfonate the propynone was the only product isolated in the isomerisation of alcohol. The silylated propenone undergoes with cyclopentadiene a Diels-Alder cycloaddition to give ketone whose skeleton is related to that of quinine.
- Erenler, Ramazan,Uno, Masaharu,Goud, Thirumani Venkateshwar,Biellmanna, Jean-Francois
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scheme or table
p. 459 - 464
(2010/01/16)
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- 3,3′-anisyl-substituted BINOL, H4BINOL, and H 8BINOL ligands: Asymmetric synthesis of diverse propargylic alcohols and their ring-closing metathesis to chiral cycloalkenes
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(Chemical Equation Presented) A series of optically active BINOL, H 4BINOL, and H8BINOL derivatives were prepared. These compounds in combination with ZnEt2 and Ti(OiPr) 4 were used to catalyze the asymmetric reaction of alkynes with aldehydes to generate chiral propargylic alcohols at room temperature. Through this comparative study, a 3,3′-bisanisyl-substituted H8BINOL (S)-7 was found to be a generally enantioselective catalyst for the reaction of structurally diverse terminal alkynes with a variety of aldehydes. It catalyzed the reactions of alkyl propiolates with 88-99% ee; the reactions of phenylacetylene with 81-87% ee; the reactions of 4-phenyl-1-butyne, an alkyl alkyne, with 77-89% ee; and the reactions of trimethylsilylacetylene with 92-97% ee. The optically active propargylic alcohols generated from this catalytic asymmetric alkyne addition were observed to undergo efficient ring-closing-metathesis (RCM) reaction in the presence of the Grubbs II catalyst to produce chiral cycloalkenes. It was further found that some of the chiral propargylic alcohols underwent a highly chemoselective tandem RCM hydrogenation reaction with retention of the enantiomeric purity. 2009 American Chemical Society.
- Yue, Yang,Turlington, Mark,Yu, Xiao-Qi,Pu, Lin
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supporting information; experimental part
p. 8681 - 8689
(2009/12/30)
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- Catalytic enantioselective addition of terminal alkynes to aromatic aldehydes using zinc-hydroxyamide complexes
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A mandelamide ligand, derived from (S)-mandelic acid and (S)-phenylethanamine, catalyzes the addition of aryl-, alkyl- and silyl-alkynylzinc reagents to aromatic and heteroaromatic aldehydes with good yields and good to high enantioselectivities.
- Blay, Gonzalo,Cardona, Luz,Fernandez, Isabel,Marco-Aleixandre, Alicia,Munoz, M. Carmen,Pedro, Jose R.
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scheme or table
p. 4301 - 4308
(2009/12/05)
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- The intricate assembling of gem-diphenylpropargylic units
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While optimized procedures for selective propargylic - versus allenic - attack (in particular by alkynylsilanes) have proven to be compatible with many substitution patterns at the propargylic center, the case of diarylpropargyl electrophiles has remained problematic. The intrinsic reactivity of 1,1-diphenylpropargylic alcohols [R-C≡C-C(Ph2)OH (R = TMS, H, Me)] in the presence of various acids (and in the absence of additional nucleophile) has thus been systematically investigated. Whereas the monophenyl analogues [R-C≡C-CH(Ph)OH] afford the expected bis(phenylpropargyl) ethers, the diphenyl versions undergo complex but quite selective processes to afford various structural types: depending on the acid used, a diallene, an allenyne, an indenylallene, an indanone or a condensed tetra- and pentacycles were obtained. When the reactions were conducted in the presence of an alkynylsilane capable of playing the role of a competing nucleophile, the expected propargylic substitution products - dialkynyldiphenylmethanes or their isomers - were never observed. The hitherto unknown simple hydrocarbons diethynyl- and dipropynyl-diphenylmethane could, however, be obtained in low yields through a four-step sequence involving allenylidene- and alkynylruthenium intermediates. Wiley-VCH Verlag GmbH & Co. KGaA, 2008.
- Maraval, Valerie,Duhayon, Carine,Coppel, Yannick,Chauvin, Remi
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experimental part
p. 5144 - 5156
(2009/08/07)
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- Titanium and zirconium benzofuranoxides. Crystal structures and catalytic properties
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Reactions of Ti(OiPr)4 or Zr(OEt)4 with 4 equivalents of 2,3-dihydro-2,2-dimethyl-7-benzofuranol (ddbfoH) in toluene gave neutral complexes that in the solid state are dimers of [Ti(μ-ddbfo) 2(ddbfo)6] and [Zr(ddbfo)3(EtOH)(μ-EtO)] 2 composition. The former could also be conveniently synthesized in a direct reaction of TiCl4 with ddbfoH. This air-stable aryloxo compound was found to initiate living ring-opening polymerization of lactides affording polyesters with narrow molecular weight distribution. It also catalyzed addition of terminal acetylenes to aryl aldehydes. The Royal Society of Chemistry.
- Krauzy-Dziedzic, Katarzyna,Ejfler, Jolanta,Szafert, Slawomir,Sobota, Piotr
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p. 2620 - 2626
(2008/09/20)
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- meso-Phbox-Pd(II) catalyzed tandem carbonylative cyclization of 1-ethynyl-1-propargyl acetate
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Palladium(II) catalyzed carbonylation of 1-ethynyl-1-propargyl acetate 1 is described; in the absence of the bisoxazoline (box) ligand, the second triple bond did not react, affording cyclic orthoesters 3 and 4. The use of meso-Phbox-Pd(II) strikingly changed the course of the reaction, yielding bicyclic lactone 2 by tandem carbonylative cyclization as a result of insertion of the second triple bond. The Royal Society of Chemistry.
- Kato, Keisuke,Teraguchi, Ryuhei,Motodate, Satoshi,Uchida, Akira,Mochida, Tomoyuki,Peganova, Tat'yana A.,Vologdin, Nikolai V.,Akita, Hiroyuki
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supporting information; experimental part
p. 3687 - 3689
(2009/02/05)
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- Facile photochemical synthesis of 1,1′-binaphthyls
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The photochemical synthesis of highly functionalized 1,1′-binaphthyls 9 by photodehydro-DielsAlder reaction of esters 8 is reported. It was found that -stacking interactions between a naphthyl moiety already present in the reactants 8 and an aryl group tethered in the propargyl position of these esters clearly influence the regio- and diastereoselectivity of the reaction. The formation of undesired phenanthrenes 10 could be suppressed by introduction of a blocking methoxy group in the 2-position of the naphthyl moiety. In one case, a diastereomeric ratio of 32:68 was achieved. This is the first example of an atropselective synthesis of biaryls by a photodehydro-DielsAlder reaction. CSIRO 2008.
- Wessig, Pablo,Mller, Gunnar
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p. 569 - 572
(2008/12/22)
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- Cu-catalyzed asymmetric conjugate additions of dialkyl- and diarylzinc reagents to acyclic β-silyl-α,β-unsaturated ketones. Synthesis of allylsilanes in high diastereo- and enantiomeric purity
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A readily available and simple (MW = 444.5 g/mol) valine-based chiral phosphine is used to promote highly efficient catalytic asymmetric conjugate additions of dialkyl- and diarylzinc reagents to acyclic β-silyl-α, β-unsaturated ketones. The catalytic asy
- Kacprzynski, Monica A.,Kazane, Stephanie A.,May, Tricia L.,Hoveyda, Amir H.
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p. 3187 - 3190
(2008/02/11)
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- Reactivity of individual organolithium aggregates: A RINMR study of n-butyllithium and 2-methoxy-6-(methoxymethyl)phenyllithium
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Low-temperature rapid injection NMR (RINMR) experiments were performed on two lithium reagents, n-butyllithium and 2-methoxy-6-(methoxymethyl)phenyllithium (5), with the goal of measuring the relative reactivity of the different aggregates (dimer, mixed dimer, and tetramer for n-BuLi, monomer and tetramer for 5) toward typical electrophiles. The reaction of the n-BuLi dimer with (trimethylsilyl)acetylene first forms the mixed dimer n-BuLi·Me3SiC≡CLi, which is about 1/60 as reactive as the n-BuLi homodimer. The tetramer does not react. In the deprotonation of (phenylthio)acetylene, the n-BuLi dimer was found to be 3.5 × 108 as reactive as the tetramer, and in the addition to p-diethylaminobenzaldehyde, the relative reactivity was at least 2 × 104. In the deprotonation of (p-tolylsulfonyl)acetylene, the monomer of 5 was at least 1014 times as reactive as the tetramer. These measurements show that the difference in reactivity between the lower and higher aggregates of organolithium reagents can be many orders of magnitude higher than all previous estimates. Copyright
- Jones, Amanda C.,Sanders, Aaron W.,Bevan, Martin J.,Reich, Hans J.
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p. 3492 - 3493
(2008/01/01)
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