- Bimetal Cooperatively Catalyzed Arylalkynylation of Alkynylsilanes
-
An unprecedented Pd/Rh cooperatively catalyzed arylalkynylation of alkynylsilanes was developed to merge an alkynylidene moiety with benzosilacycle. These silaarenes possess a particular aggregation-induced emission behavior. Mechanistic investigations demonstrate that the relay trimetallic transmetalation plays a pivotal role in governing this transformation.
- Chen, Xing,Li, Mengke,Liu, Zhipeng,Yang, Can,Xie, Haisheng,Hu, Xinwei,Su, Shi-Jian,Jiang, Huanfeng,Zeng, Wei
-
supporting information
p. 6724 - 6728
(2021/09/08)
-
- Substituted 9-Anthraldehydes from Dibenzocycloheptanol Epoxides via Acid-Catalyzed Epoxide Opening/Semipinacol Rearrangement
-
Starting from benzaldehyde derivatives, the corresponding dibenzocycloheptenol could be prepared in five steps. Under both substrate (secondary vs tertiary alcohol and the substituents on the aromatic ring(s)) and condition control, the subsequent epoxidation and acid-catalyzed epoxide opening/semipinacol rearrangement/aromatization afforded the corresponding 9-anthraldehydes in good yields, up to 88% over two steps. The presence of the electron-withdrawing group(s) on the aromatic ring(s) suppressed the rate of the epoxidation while the subsequent semipinacol rearrangement step required heating; the presence of the electron-donating group(s), on the other hand, frequently led to the decomposition during the epoxidation. From the mechanistic studies, the semipinacol rearrangement of the epoxide could precede the ionization at the bisbenzylic position, yielding the aldehyde intermediate. The ensuing dehydrative aromatization led to the formation of 9-anthraldehyde. Conversely, nucleophilic addition to the aldehyde and dehydrative aromatization with concomitant loss of formic acid led to anthracene.
- Phumjan, Tanawat,Songthammawat, Poramate,Jongcharoenkamol, Jira,Batsomboon, Paratchata,Ruchirawat, Somsak,Ploypradith, Poonsakdi
-
p. 13322 - 13349
(2021/09/13)
-
- 1,3-Difunctionalization of β-alkyl nitroalkenes via combination of Lewis base catalysis and radical oxidation
-
Upon treatment with a Lewis base catalyst, β-alkyl-substituted nitroalkenes could be readily converted into allylic nitro compounds. Examples of either C-1 or C-3 functionalization methods have been reported through nitro-elimination, giving alkene products. In this work, successful 1,3-difunctionalization was achieved through a synergetic Lewis base catalysis and TBHP radical oxidation, giving vinylic alkoxyamines in good to excellent yields. This work further extended the general synthetic application of β-alkyl nitroalkenes.
- Wang, Ye,Zheng, Lei,Shi, Xiaodong,Chen, Yunfeng
-
supporting information
p. 886 - 889
(2021/02/01)
-
- A Transient Directing Group Strategy Enables Enantioselective Multicomponent Organofluorine Synthesis
-
The vicinal fluorofunctionalization of alkenes represents an expedient strategy for converting feedstock olefins into valuable fluorinated molecules and as such has garnered significant attention from the synthetic community; however, current methods remain limited in terms of scope and selectivity. Here we report the site-selective palladium-catalyzed three-component coupling of alkenylbenzaldehydes, arylboronic acids, and N-fluoro-2,4,6-trimethylpyridinium hexafluorophosphate facilitated by a transient directing group. The synthetically enabling methodology constructs vicinal stereocenters with excellent regio-, diastereo-, and enantioselectivities, forging products that map onto bioactive compounds.
- Liu, Zhonglin,Oxtoby, Lucas J.,Liu, Mingyu,Li, Zi-Qi,Tran, Van T.,Gao, Yang,Engle, Keary M.
-
supporting information
p. 8962 - 8969
(2021/07/01)
-
- Enantioselective synthesis of 1-aminoindene derivativesviaasymmetric Br?nsted acid catalysis
-
We describe a catalytic asymmetric iminium ion cyclization reaction of simple 2-alkenylbenzaldimines using a BINOL-derived chiralN-triflyl phosphoramide. The corresponding 1-aminoindenes and tetracyclic 1-aminoindanes are formed in good yields and high enantioselectivities. Further, the chemical utility of the obtained enantiopure 1-aminoindene is demonstrated for the asymmetric synthesis of (S)-rasagiline.
- Ding, Du,Jiang, Hua-Jie,Wang, Tao,Wu, Xiang,Zhang, Ying,Zhao, Li-Ping
-
supporting information
p. 9680 - 9683
(2021/09/30)
-
- Rh-Catalyzed Asymmetric Hydrogenation of α,β- and β,β-Disubstituted Unsaturated Boronate Esters
-
A highly enantioselective hydrogenation of α,β-unsaturated boronate esters catalyzed by Rh-(S)-DTBM-Segphos complex has been developed. Both (Z)-α,β- and β,β-disubstituted substrates can be successfully hydrogenated to afford chiral boronates with excellent enantioselectivities, up to 98 % ee. Furthermore, the obtained chiral boronate esters, as important versatile synthetic intermediates are successfully transformed to the corresponding chiral alcohols, amines and other important derivatives with maintained enantioselectivities.
- Hou, Guohua,Shen, Xin,Yan, Qiaozhi,Zi, Guofu
-
-
- Preparation method of silicon spiro compound (by machine translation)
-
The invention discloses a preparation method of a silicon spiro compound. The invention provides a preparation method of a silicon spiro compound as shown in a formula II, which comprises the following steps: in a solvent, a compound represented by the formula III is subjected to cyclization reaction under the presence of a monovalent rhodium catalyst and a phosphine ligand to obtain the silicon spiro compound as shown in the formula II. The preparation method of the silicon spiro compound can be simple. , The establishment of the silicon spiro compound is realized conveniently and efficiently. (by machine translation)
- -
-
Paragraph 0222-0224
(2020/06/17)
-
- Consecutive borylcupration/C-C coupling of ?-alkenyl aldehydes towards diastereoselective 2-(borylmethyl)cycloalkanols
-
Copper(i) catalyzes the borylative cyclization of ?-alkenyl aldehydes through chemo- and regioselective addition of Cu-B to C?C and concomitant intramolecular 1,2-addition of Cu-C on C?O. The products are formed in an exclusive diastereoselective manner and computational analysis identifies the key points for the observed chemo- and diastereoselectivity.
- Carbó, Jorge J.,Fernández, Elena,Maza, Ricardo J.,Royes, Jordi
-
supporting information
p. 5973 - 5976
(2020/06/05)
-
- Asymmetric Synthesis and Application of Chiral Spirosilabiindanes
-
Reported here is the development of a class of chiral spirosilabiindane scaffolds by Rh-catalyzed asymmetric double hydrosilation, for the first time. Enantiopure SPSiOL (spirosilabiindane diol), a new type of chiral building block for the preparation of various chiral ligands and catalysts, was readily prepared on greater than 10 gram scale using this protocol. The potential of this new spirosilabiindane scaffold in asymmetric catalysis was preliminarily demonstrated by development of the corresponding monodentate phosphoramidite ligands (SPSiPhos), which were used in both a Rh-catalyzed hydrogenation and a Pd-catalyzed intramolecular carboamination.
- Chang, Xin,Chen, Hong-Chao,Li, Chuan-Ying,Ma, Pei-Long,Wang, Peng
-
supporting information
p. 8937 - 8940
(2020/04/30)
-
- Rhodium-Catalyzed Intermolecular Cyclopropanation of Benzofurans, Indoles, and Alkenes via Cyclopropene Ring Opening
-
The generation of metal carbenoids via ring opening of cyclopropenes by transition metals offers a simple entry into highly reactive intermediates. Herein, we describe a diastereoselective intermolecular rhodium-catalyzed cyclopropanation of heterocycles and alkenes using cyclopropenes as carbene precursors with a low loading of a commercially available rhodium catalyst. The reported method is scalable and could be performed with catalyst loadings as low as 0.2 mol %, with no impact to the reaction yield or selectivity.
- Jeyaseelan, Rubaishan,Lautens, Mark,Ross, Rachel J.
-
supporting information
(2020/06/29)
-
- The Different Faces of [Ru(bpy)3Cl2] and fac[Ir(ppy)3] Photocatalysts: Redox Potential Controlled Synthesis of Sulfonylated Fluorenes and Pyrroloindoles from Unactivated Olefins and Sulfonyl Chlorides
-
A cascade alkene sulfonylation that simultaneously forges C-S and C-C bonds is a highly efficient and powerful approach for directly accessing structurally diverse sulfonylated compounds in a single operation. The reaction was enabled by visible-light-mediated regioselective radical addition of sulfonyl chlorides to 2-arylstyrenes using fac[Ir(ppy)3] as a photocatalyst, demonstrating its unique role in a photocascade process to execute atom transfer radical addition (ATRA) followed by photocyclization. A new class of sulfonyl-substituted fluorenes and pyrroloindoles, which are useful in the field of photoelectronic materials and medicinal chemistry, was produced in excellent yields by this photocascade reaction. In contrast, the cyclization was interrupted when using the [Ru(bpy)3Cl2] catalyst having lower reduction potential, leading only to the formation of a C-S bond and the production of acyclic sulfonylated 2-arylstyrenes under identical reaction conditions. The synthetic utility of the present room-temperature photocatalysis is enhanced by the broad availability of bench-stable sulfonyl chlorides and unactivated olefins, thereby providing a cost-effective and broad-scope protocol.
- Pagire, Santosh K.,Kumagai, Naoya,Shibasaki, Masakatsu
-
supporting information
p. 7853 - 7858
(2020/10/12)
-
- Ene reactions of 2-borylated α-methylstyrenes: A practical route to 4-methylenechromanes and derivatives
-
4-Methylenechromanes were prepared via a three-step process from 2-borylated α-methylstyrenes. This sequence is based on a key glyoxylate-ene reaction catalyzed by scandium(iii) triflate. The resulting γ-hydroxy boronates, which cyclise to seven-membered
- Boureghda, Chaima,Macé, Aurélie,Berrée, Fabienne,Roisnel, Thierry,Debache, Abdelmadjid,Carboni, Bertrand
-
p. 5789 - 5800
(2019/06/19)
-
- Pd-Catalyzed Enantioselective Ring Opening/Cross-Coupling and Cyclopropanation of Cyclobutanones
-
A palladium-catalyzed enantioselective sequential ring-opening/cross-coupling of cyclobutanones is disclosed that provides chiral indanones bearing C3-quaternary stereocenters. The reaction process involves palladium-catalyzed nucleophilic addition of cyc
- Cao, Jian,Chen, Ling,Sun, Feng-Na,Sun, Yu-Li,Jiang, Ke-Zhi,Yang, Ke-Fang,Xu, Zheng,Xu, Li-Wen
-
supporting information
p. 897 - 901
(2019/01/04)
-
- Highly Enantioselective Iridium-Catalyzed Hydrogenation of 2-Aryl Allyl Phthalimides
-
The iridium-catalyzed asymmetric hydrogenation of 2-aryl allyl phthalimides to afford enantioenriched β-aryl-β-methyl amines is presented. Recently developed Ir-MaxPHOX catalysts are used for this enantioselective transformation. The mild reaction conditions and the feasible removal of the phthalimido group makes this catalytic method easily scalable and of great interest to afford chiral amines. The importance of this new methodology is exemplified by the formal synthesis of (R)-Lorcaserin, OTS514, and enantiomerically enriched 3-methyl indolines.
- Cabré, Albert,Romagnoli, Elia,Martínez-Balart, Pol,Verdaguer, Xavier,Riera, Antoni
-
supporting information
p. 9709 - 9713
(2019/11/19)
-
- PdII-Catalyzed Oxidative Tandem aza-Wacker/Heck Cyclization for the Construction of Fused 5,6-Bicyclic N,O-Heterocycles
-
A PdII-catalyzed oxidative tandem cyclization was developed for the construction of fused 5,6-bicyclic N, O-heterocycles. This reaction was enabled by the combined use of a 3-methylpyridine ligand and pentafluorobenzoic acid additive. A range of heterocyclic products with different substituents could be prepared in moderate to good yields via this methodology. Several transformations, including a scaled-up preparation of product 2 a, were also carried out showing the good applicability of our methodology.
- Ye, Chenghao,Kou, Xuezhen,Xia, Jingzhao,Yang, Guoqiang,Kong, Li,Wei, Quhao,Zhang, Wanbin
-
supporting information
p. 1897 - 1901
(2018/07/31)
-
- Electrochemical oxidative radical oxysulfuration of styrene derivatives with thiols and nucleophilic oxygen sources
-
Oxydifunctionalization of olefins represents a powerful tool and yet poses a challenging task. Previous methods have usually required a stoichiometric amount of a strong oxidant and an expensive transition-metal catalyst. This work describes the first example of the electrochemical oxysulfuration reaction of olefins with thiols and nucleophilic oxygen sources. This electrochemical difunctionalization reaction is conducted under catalyst- and oxidant-free conditions, and shows good substrate generality, affording thio-substituted alcohols, ethers and γ-lactones in good chemical yields and with excellent regioselectivities. This work represents a new and green strategy for the difunctionalization of olefins, and also provides a complementary and highly valuable prospect for current methodologies for the synthesis of thio-substituted compounds.
- Wang, Yang,Deng, Lingling,Mei, Haibo,Du, Bingnan,Han, Jianlin,Pan, Yi
-
supporting information
p. 3444 - 3449
(2018/08/06)
-
- The cumene/O2 system: A very simple tool for the radical chain oxidation of some functional groups
-
Due to the relative stability of the cumyl radical, cumenes and α-methyl-styrenes are ideally structured to directly harvest the oxidizing reactivity of O2 and initiate radical chain reactions in catalyst-free conditions. In the absence of additional substrates, these processes can lead to acetophenones. In the presence of substrates, the cumene oxidation process can be intercepted in various chain reactions, affording very simple protocols for functional group oxidation.
- Malekafzali,Malinovska,Patureau
-
supporting information
p. 6981 - 6985
(2017/08/02)
-
- Reversing the Regioselectivity of Halofunctionalization Reactions through Cooperative Photoredox and Copper Catalysis
-
Halofunctionalization of alkenes is a classical method for olefin difunctionalization. It gives rise to adducts which are found in many natural products and biologically active molecules, and offers a synthetic handle for further manipulation. Classically, this reaction is performed with an electrophilic halogen source and leads to regioselective formation of the halofunctionalized adducts. Herein, we demonstrate a reversal of the native regioselectivity for alkene halofunctionalization through the use of an acridinium photooxidant in conjunction with a copper cocatalyst.
- Griffin, Jeremy D.,Cavanaugh, Cortney L.,Nicewicz, David A.
-
p. 2097 - 2100
(2017/02/15)
-
- Intramolecular Crossed [2+2] Photocycloaddition through Visible Light-Induced Energy Transfer
-
Herein, we present the intramolecular [2+2] cycloadditions of dienones promoted through sensitization, using a polypyridyl iridium(III) catalyst, to form bridged cyclobutanes. In contrast to previous examples of straight [2+2] cycloadditions, these efficient crossed additions were achieved under irradiation with visible light. The reactions delivered desired bridged benzobicycloheptanone products with excellent regioselectivity in high yields (up to 96%). This process is superior to previous syntheses of benzobicyclo[3.1.1]heptanones, which are readily converted to B-norbenzomorphan analogues of biological significance. Electrochemical, computational, and spectroscopic studies substantiated the mechanism of triplet energy transfer and explained the unusual regiocontrol.
- Zhao, Jiannan,Brosmer, Jonathan L.,Tang, Qingxuan,Yang, Zhongyue,Houk,Diaconescu, Paula L.,Kwon, Ohyun
-
supporting information
p. 9807 - 9810
(2017/08/03)
-
- Preparation of isoindolinones via a palladium-catalyzed diamination
-
A Pd(II)-catalyzed cyclization using oxidative olefin diamination was developed for the preparation of isoindolinones from ortho-olefinic N-methoxybenzamides. Using the optimized reaction conditions, the desired products were obtained in up to 90% yield using NFSI as the oxidant. This reaction provides an efficient and direct access to isoindolinones with amine functionality, an important drug skeleton.
- Li, Yu,Kou, Xuezhen,Ye, Chenghao,Zhang, Xinghua,Yang, Guoqiang,Zhang, Wanbin
-
supporting information
p. 285 - 288
(2017/01/03)
-
- C- ARYL GLYCOSID DERIVATIVES, PHARMACEUTICAL COMPOSITION, PREPARATION PROCESS AND USES THEREOF
-
This invention relates to a kind of C-aryl glycoside derivatives, its pharmaceutical compositions, preparation methods, and uses thereof. The preparation method comprises: method 1: in a solvent, deprotecting the acetyl protecting groups of compound 1-f in the presence of a base; method 2: 1) compound 2-g reacts with via Mitsunobu reaction; 2) deprotecting the acetyl protecting groups of compound 2-f obtained from step 1; method 3: 1) compound 2-g reacts with via nucleophilic substitution reaction; 2) deprotecting the acetyl protecting groups of compound 3-f obtained from step 1. The pharmaceutical composition comprises a kind of C-aryl glycoside derivatives; it's pharmaceutically acceptable salts and/or prodrugs thereof and excipient thereof. This invention further relates to a kind of C-aryl glycoside derivatives, it's pharmaceutically acceptable salts or pharmaceutical compositions thereof for the use in preparation of a SGLT inhibitor. The C-aryl glycoside derivatives of this invention provides a new direction for the study of SGLT inhibitors.
- -
-
Paragraph 0152; 0153
(2017/04/19)
-
- Asymmetric carbonyl-ene reaction of trifluoropyruvate catalyzed by Pd(II)-SunPhos complex
-
An efficient asymmetric carbonyl-ene reaction of trifluoropyruvate catalyzed by chiral Pd(II)/(S)-SunPhos complex was developed. A series of optically active homoallylic alcohols containing a CF3 group were obtained with high yields and excellent ee under mild conditions. Particularly, the reaction of isobutylene and trifluoropyruvate gave the desired product (90% yield, 98% ee) with catalyst loading as low as 0.01 mol% in dichloroethane/toluene.
- Jiang, Lili,Hu, Bei,Xie, Xiaomin,Zhang, Zhaoguo
-
supporting information
p. 6901 - 6905
(2017/10/31)
-
- B(C6F5)3-Catalyzed Ring Opening and Isomerization of Unactivated Cyclopropanes
-
Catalytic amounts of B(C6F5)3 promote the ring opening and subsequent isomerization of a series of unactivated cyclopropanes to afford terminal olefins in good yields when a hydrosilane and 2,6-dibromopyridine are employed as additives.
- Zhang, Zi-Yu,Liu, Zhi-Yun,Guo, Rui-Ting,Zhao, Yu-Quan,Li, Xiang,Wang, Xiao-Chen
-
supporting information
p. 4028 - 4032
(2017/03/27)
-
- Compounds of the menthane series. Synthesis of unsaturated primary alcohols with the o- and p-menthane skeletons
-
Precursors to terpene alcohols of the o- and p-menthane series (o-cimen-7-ol and o- and p-cimen-9-ols) were synthesized, and their reduction with lithium in ethylenediamine was studied. The reduction of o- and p-cimen-9-ols in the presence of isopropyl alcohol selectively afforded the corresponding 1,4-dihydro derivatives. Under analogous conditions, o-cimen-7-ol was converted into a mixture of unsaturated hydrocarbons. The reduction with lithium in ethylenediamine in the absence of isopropyl alcohol in all cases gave mixtures of menthene alcohols.
- Fedorov,Fedorova,Sheverdov,Pavlov,Eremkin
-
p. 806 - 812
(2016/07/30)
-
- Borylation of Olefin C-H Bond via Aryl to Vinyl Palladium 1,4-Migration
-
The aryl to vinyl palladium 1,4-migration was realized for the first time. The generated alkenyl palladium species was trapped by diboron reagents under Miyaura borylation conditions, providing a new method to synthesize β,β-disubstituted vinylboronates. The excellent regioselectivity and broad substrate scope were observed for this novel transformation.
- Hu, Tian-Jiao,Zhang, Ge,Chen, Ya-Heng,Feng, Chen-Guo,Lin, Guo-Qiang
-
p. 2897 - 2900
(2016/03/19)
-
- Enantioselective Bromo-oxycyclization of Silanol
-
Relying on the nucleophilicity of silanol for building up silicon-incorporated scaffold with an enantiopure tetrasubstituted carbon center remains elusive. In this report, asymmetric bromo-oxycyclization of olefinic silanol by using chiral anionic phase-transfer catalyst is described. This protocol provided a facile entry to a wide arrangement of enantiopure benzoxasilole in moderate to excellent enantioselectivities depending on the unique reactivity of bromine/N-benzyl-DABCO complex.
- Xia, Zilei,Hu, Jiadong,Shen, Zhigao,Wan, Xiaolong,Yao, Qizheng,Lai, Yisheng,Gao, Jin-Ming,Xie, Weiqing
-
supporting information
p. 80 - 83
(2016/01/15)
-
- FeCl3-Catalyzed Intramolecular Michael Reaction of Styrenes for the Synthesis of Highly Substituted Indenes
-
An intramolecular FeCl3-catalyzed Michael addition reaction of styrene, a poor nucleophile, onto α,β-unsaturated ketones was developed for the synthesis of highly substituted indene derivatives. The method was further applied to the total synthesis of the sesquiterpene natural products (±)-jungianol and 1-epi-jungianol.
- Dethe, Dattatraya H.,Murhade, Ganesh M.,Ghosh, Sourav
-
p. 8367 - 8376
(2015/09/01)
-
- Palladium-Catalyzed Aerobic Aminooxygenation of Alkenes for Preparation of Isoindolinones
-
A palladium-catalyzed intramolecular isoindolinone-forming aminooxygenation of alkenes with 1 atm of oxygen as oxidant is reported. A variety of functionalized alkenes and carboxylic acids can be used, and high yields were observed. Preliminary mechanistic studies revealed that the aminooxygenation products were formed through the oxidation of a C-PdII species using a strong oxidant, peroxide, which is generated in situ from a Pd(OAc)2/bpy/O2/HOAc catalytic system.
- Kou, Xuezhen,Li, Yu,Wu, Liang,Zhang, Xinghua,Yang, Guoqiang,Zhang, Wanbin
-
supporting information
p. 5566 - 5569
(2015/12/01)
-
- Cobalt-catalyzed enantioselective intramolecular hydroacylation of ketones and olefins
-
Cobalt-chiral diphoshine catalytic systems promote intramolecular hydroacylation reactions of 2-acylbenzaldehydes and 2-alkenylbenzaldehydes to afford phthalide and indanone derivatives, respectively, in moderate to good yields with high enantioselectivities. The ketone hydroacylation did not exhibit a significant H/D kinetic isotope effect (KIE) with respect to the aldehyde C-H bond, indicating that C-H activation would not be involved in the rate-limiting step.
- Yang, Junfeng,Yoshikai, Naohiko
-
supporting information
p. 16748 - 16751
(2015/02/05)
-
- Cleavage of C-C and C-Si σ-bonds and their intramolecular exchange
-
C-C and C-Si σ-bonds are cleaved to undergo bond exchange when substrates equipped with cyclobutanone and silacyclobutane moieties are treated with a palladium(0) catalyst. The skeletal exchange results in construction of silabicyclo[5.2.1]decanes in a diastereoselective manner.
- Ishida, Naoki,Ikemoto, Wataru,Murakami, Masahiro
-
supporting information
p. 5912 - 5915
(2014/05/20)
-
- Diisobutylaluminum hydride promoted cyclization of o -(trimethylsilylethynyl)styrenes to indenes
-
The reaction of o-(trimethylsilylethynyl)styrenes with diisobutylaluminum hydride (DIBAL-H) provides 2-trimethylsilyl-1H-indenes efficiently. The cyclization mechanism involves regioselective hydroalumination of the alkynyl moiety, geometrical isomerizati
- Kinoshita, Hidenori,Hirai, Nobuyoshi,Miura, Katsukiyo
-
p. 8171 - 8181
(2015/03/18)
-
- Copper-mediated/catalyzed oxyalkylation of alkenes with alkylnitriles
-
A copper-promoted oxyalkylation of alkenes with alkylnitriles has been developed. The protocol provides rapid access to phthalides (γ-lactones) or isochromanones (d-lactones) via the formation of a C(sp3)-C(sp3) and a C(sp3)-O bond with the generation of up to two quaternary carbon atoms. Mechanistic studies suggest that this reaction is initiated by the formation of the C(sp3)-C(sp3) bond rather than the C(sp3)-O bond. Catalytic conditions were subsequently developed using carboxylic acid as an internal nucleophile.
- Bunescu, Ala,Wang, Qian,Zhu, Jieping
-
supporting information
p. 14633 - 14636
(2015/01/09)
-
- Syntheses of 3,4-benzotropolones by ring-closing metatheses
-
Ortho-lithiated styrenes or ortho-lithiated benzaldehyde dimethyl acetals were added to 2,2-dimethoxypent-4-enals 7. The resulting alcohols were carried on to the aromatic dienones 10. These were ring-closed by olefin metathesis. Hydrolysis of the dimethyl ketal moiety and enolization provided the 3,4-benzotropolones 5. Overall, this access comprises 4-6 steps and totaled a 22-81% yield.
- Arican, Deniz,Brückner, Reinhard
-
supporting information
p. 2582 - 2585
(2013/07/19)
-
- A visible-light-mediated oxidative C-N bond formation/aromatization cascade: Photocatalytic preparation of N-arylindoles
-
Just add light and air: Structurally diverse N-arylindoles can be prepared from readily prepared o-styryl anilines through visible-light photocatalysis. The reaction, which is conducted open to air, is mediated by [Ru(bpz) 3](PF6)2 (bpz=2,2'-bipyrazine) and involves both C-N bond formation and aromatization (see scheme). Using suitably substituted substrates, a 1,2-carbon shift can be also incorporated into this cascade reaction. Copyright
- Maity, Soumitra,Zheng, Nan
-
supporting information
p. 9562 - 9566
(2012/11/07)
-
- Intramolecular σ-bond metathesis between carbon-carbon and silicon-silicon bonds
-
An intramolecular σ-bond metathesis between carbon-carbon and silicon-silicon bonds took place on treatment of a disilane tethered to a cyclobutanone with a palladium(0) catalyst, furnishing a silaindane skeleton as well as an acylsilane functionality at
- Ishida, Naoki,Ikemoto, Wataru,Murakami, Masahiro
-
supporting information; experimental part
p. 3230 - 3232
(2012/09/08)
-
- Silylboranes as new sources of silyl radicals for chain-transfer reactions
-
Various silylboranes, which were outfitted with a catecholborane moiety at one end and a (Me3Si)3Si moiety at the other end of a carbon chain, were prepared through the hydroboration of the corresponding unsaturated silanes. The C-ce
- Rouquet, Guy,Robert, Frederic,Mereau, Raphaal,Castet, Frederic,Renaud, Philippe,Landais, Yannick
-
supporting information; experimental part
p. 940 - 950
(2012/02/16)
-
- Highly enantioselective hydrogenation of β,β-disubstituted nitroalkenes
-
Building the building blocks: A highly enantioselective hydrogenation of ?-aryl-?-alkyl disubstituted nitroalkenes 1 has been developed. This method results in enantiomerically pure nitroalkanes 2, which are versatile precursors for chemical synthesis.
- Li, Shengkun,Huang, Kexuan,Cao, Bonan,Zhang, Jiwen,Wu, Wenjun,Zhang, Xumu
-
supporting information; experimental part
p. 8573 - 8576
(2012/09/10)
-
- Lipase-mediated resolution of substituted 2-aryl-propanols: Application to the enantioselective synthesis of phenolic sesquiterpenes
-
A comprehensive study of the lipase-mediated resolution of substituted 2-aryl-propanols is reported. The latter alcohols were submitted to the irreversible acetylation catalyzed either by PPL, CRL, or lipase PS. The enantioselectivity of these transformations was dependent on the type of lipase used. The type of substituents and particularly their position on the aromatic ring strongly affected the selectivity of the reaction. The experiments described prove that PPL is the more versatile lipase catalyzing the acetylation with an enantiomeric ratio (E) value that ranges from 1 up to 144, depending on the substrate used. Conversely, the same transformations were catalyzed by CRL and lipase PS with an enantiomeric ratio value, which is always less than 5. The remarkable behavior of PPL was exploited in the large scale resolution of some substituted 2-aryl-propanols whose enantiomeric forms are relevant building blocks in the enantioselective synthesis of phenolic sesquiterpenes. By these means, the synthesis of (S)-turmeronol B and the formal syntheses of (R)-curcumene, (R)-curcuphenol, (R)-xanthorrhizol, and (R)-curcuhydroquinone were accomplished.
- Serra, Stefano
-
p. 619 - 628
(2011/07/08)
-
- Ring-closure reactions of 1,2-diaza-4,5-benzoheptatrienyl metal compounds: Experiment and theory
-
2-Alkenylbenzylidene hydrazones 5a-m, which are accessible in good to excellent yields in a four-step synthesis, are converted into 1,2-diaza-4,5-benzoheptatrienyl metal compounds 1a-m by treatment with KO-t-Bu as base. These metal compounds undergo the various types of reactions in good yields and exclusively depending on the nature of substituents R1 and R3. Thus, metal compounds 1a-c carrying alkyl substituents R 1 and R3 form 3H-benzodiazepines 6a-c after electrophilic quench of the intermediate cyclic anion 7 in a 7-endo-trig electrocyclic reaction with a moebius aromatic transition structure 1--TS. Similarly, a benzothienyl derivative 5n is converted into diazepine 6d. Potassium compounds 1d-h, which are N-methyl and aryl substituted at R 3, form 1,2-dihydrophthalazines 8a-e in a predominantly charge-controlled 6-exo-trig cyclization reaction. In contrast, aryl-aryl-substituted systems 5i-m did not lead to cyclic products upon deprotonation, but the intermediate open-chain metal compounds 1i-m were trapped by acid chlorides at N1 to yield the hydrazides 10a-e. We interpret thermodynamics and kinetics of these reactions in the context of the Baldwin rules on the basis of quantum chemical calculations and discuss the transition structures considering the results of NICS and NBO-charge calculations. Examples of the products 6, 8, and 10 could be characterized by X-ray diffraction.
- Kleine, Tillmann,Bergander, Klaus,Froehlich, Roland,Wibbeling, Birgit,Wuerthwein, Ernst-Ulrich
-
scheme or table
p. 1979 - 1991
(2011/05/07)
-
- Chiral sulfoxide-olefin ligands: Completely switchable stereoselectivity in rhodium-catalyzed asymmetric conjugate additions
-
Have it both ways: A novel class of chiral sulfoxide-olefin ligands was synthesized from a single chiral source. These ligands were evaluated in rhodium-catalyzed 1,4-additions of arylboronic acids to electron-deficient olefins, and remarkable olefin-directed reversal of stereoselectivity (up to >99 ee, R isomer; 98 ee, S isomer) was observed when the reversal ligand pair L1 (branched olefin) and L2 (linear olefin) were utilized (see scheme). Copyright
- Chen, Guihua,Gui, Jiangyang,Li, Liangchun,Liao, Jian
-
supporting information; experimental part
p. 7681 - 7685
(2011/10/17)
-
- A 1,3-carbonyl shift in the platinum-catalyzed aromatization of 2-epoxy-1-(methoxyalk-2-ynyl)benzenes
-
A platinum-catalyzed reaction involving new aromatization/1,3-carbonyl shift cascade of 2-epoxy-1-(methoxyalk-2-ynyl)benzenes is reported. This skeletal rearrangement is mechanistically significant because it involves a remarkable 1,3-carbonyl shift to complete the aromatization and to regenerate the catalyst.
- Chaudhuri, Rupsha,Das, Arindam,Liao, Hsin-Yi,Liu, Rai-Shung
-
supporting information; experimental part
p. 4601 - 4603
(2010/10/18)
-
- Pd-Catalyzed intramolecular oxyalkynylation of alkenes with hypervalent iodine
-
(Figure presented) The first example of intramolecular oxyalkynylation of nonactivated alkenes using oxidative Pd chemistry is reported. Both phenol and aromatic or aliphatic acid derivatives could be used under operator-friendly conditions (room temperature, technical solvents, under air). The discovery of the superiority of benzlodoxolone-derlved hypervalent iodine reagent 3d as an alkyne transfer reagent further expands the rapidly increasing utility of hypervalent iodine reagents in catalysis and is expected to have important implications for other similar processes.
- Nicolal, Stefano,Erard, Stephane,Gonzalez, Davinla Fernandez,Waser, Jerome
-
supporting information; experimental part
p. 384 - 387
(2010/03/04)
-
- Synthesis of 3,3-disubstituted oxindoles through Pd-catalyzed intramolecular cyanoamidation
-
The cyanoamidation of olefins was achieved. When N-(2-vinylphenyl)cyanoformamides were treated with palladium catalyst, intramolecular cyanoamidation took place to give corresponding 3,3-disubstituted oxindoles. P(t-Bu)3 showed a remarkable eff
- Yasui, Yoshizumi,Kamisaki, Haruhi,Ishida, Takayuki,Takemoto, Yoshiji
-
supporting information; experimental part
p. 1980 - 1989
(2010/04/24)
-
- Synthesis and spin trapping properties of 1,1-dimethyl-3-(trifluoromethyl)- 1H-isoindole N-oxide
-
We have achieved an efficient synthesis of 1,1-dimethyl-3-(trifluoromethyl) -1H-isoindole N-oxide (2) in 39% yield by seven steps from 2-bromobenzoic acid (3). This compound serves as a spin trap reagent, giving a strong and stable ESR signal of the radic
- Hatano, Bunpei,Miyoshi, Katsunori,Sato, Haruna,Ito, Tomohiro,Ogata, Tateaki,Kijima, Tatsuro
-
supporting information; experimental part
p. 5399 - 5401
(2010/11/02)
-
- Orthogonal synthesis of isoindole and isoquinoline derivatives from organic azides
-
(Chemical Equation Presented) α-Azido carbonyl compounds bearing a 2-alkenylaryl moiety at the α-position are found to be promising precursors for synthesis of isoindole and isoquinoline derivatives via 1,3-dipolar cycloaddrtion of azides onto alkenes and fcrelectrocyclization of N-H imine intermediates, respectively.
- Hui, Benjamin Wei-Qiang,Chiba, Shunsuke
-
supporting information; experimental part
p. 729 - 732
(2009/08/12)
-
- ortho-Effect on the acid-catalyzed hydration of 2-substituted α-methylstyrenes
-
α-Methylstyrene and nine ortho-substituted analogs have been synthesized and the kinetics of their acid-catalyzed hydration in aqueous solutions of sulfuric acid at 25°C have been investigated. The kinetic acidity function HS has been constructed from the dependence of the observed rate constants kobs on the sulfuric acid concentration. The catalytic rate constants of the acid-catalyzed hydration kortho have been calculated as well. The identical shape of the kinetic acidity functions for ortho- and para-derivatives confirms what the consistent mechanism A-SE2 of the acid-catalyzed hydration has already proved for the corresponding paraderivatives. The A-SE2 mechanism involves a rate-determining proton transfer of the hydrated proton to the substrate. From the dependence of the catalytic rate constants of the ortho-derivatives on the catalytic rate constants of the para-derivatives, it is seen that the logarithm of the catalytic rate constant for hydrogen as a substituent is markedly out of the range of the other substituents and, simultaneously, that the ortho-derivatives react significantly slower than the corresponding para-derivatives. In correlation with the substitent constants σp+, a reaction constant of ρ+= -1.45 have been found. The constant is, in absolute value, considerably smaller than that for para-derivatives (ρ+ = -3.07). In parallel, the steric effects are enforced more significantly for the monoatomic substituents (slope of the Charton's constants 3.92) than for substituents including more atoms (slope of the Charton's constants 2.09). A small value of the reaction constant ρ+ has been elucidated due to the lower conjugation between the reaction centre and the benzene ring as a consequence of the geometric twist of the reaction centre out of the main aromatic plane accompanied by fading mesomeric interaction between the reaction centre and the substituents attached to the benzene ring. The isopropyl group in the carbocation is twisted less out of the aromatic plane for the monoatomic substituents and, therefore, also a small difference in the bulk of substituents has considerable steric influence on the conjugation between the carbocation and the benzene ring bearing substituents. On the contrary, the isopropyl group in the carbocations with polyatomic substituents is twisted to such a degree that changes in the bulk of substituents affect the resonant stabilization negligibly. Similar conclusions were also deduced from the correlations of the substitution constants σI and σR+.
- Prusek, Ondrej,Bures, Filip,Pytela, Oldrich
-
experimental part
p. 85 - 99
(2009/06/06)
-
- BORON-CONTAINING SMALL MOLECULES
-
This invention provides, among other things, novel compounds useful for treating bacterial infections, pharmaceutical compositions containing such compounds, as well as combinations of these compounds with at least one additional therapeutically effective agent.
- -
-
Page/Page column 232
(2009/01/23)
-
- Ground state oxygen in synthesis of cyclic peroxides. Part 1: Benzo fused ketals
-
A thiol-olefin-cooxygenation (TOCO) radical chain reaction involving ground state molecular oxygen converts 2′-isopropenyl acetophenones directly into cyclic peroxy hemiketal products with three new bonds. Starting with 4-t-butylbenzenethiol, this TOCO pr
- Kim, Junwon,Li, Hong Bin,Rosenthal, Andrew S.,Sang, Dongpei,Shapiro, Theresa A.,Bachi, Mario D.,Posner, Gary H.
-
p. 4120 - 4127
(2007/10/03)
-
- Intramolecular Anodic Carbon-Carbon Bond-Forming Reactions of Oxidized Phenol Intermediates Leading to Spirodienones. Structural Effects on Reactivity and Evidence for a Phenoxonium Ion Intermediate
-
Anodic oxidation of 4-phenylphenol in methanol leads to 4-methoxy-4-phenylcyclohexa-2,5-dienones whereas anodic oxidation of 4-(2-alkenylphenyl)-phenols leads to spirocyclic 2,5-cyclohexadienones in competition with methanol addition to the 4-position.Usi
- Swenton, John S.,Carpenter, Kenneth,Chen, Ying,Kerns, Michael L.,Morrow, Gary W.
-
p. 3308 - 3316
(2007/10/02)
-