- α-Oxocarboxylic Acids as Three-Carbon Insertion Units for Palladium-Catalyzed Decarboxylative Cascade Synthesis of Diverse Fused Heteropolycycles
-
A novel palladium-catalyzed decarboxylative cascade cyclization for the assembly of diverse fused heteropolycycles by employing α-oxocarboxylic acids as three-carbon insertion units is reported. This protocol enables the synthesis of isoquinolinedione- and indolo[2,1-a]isoquinolinone-fused benzocycloheptanones in moderate to good yields by the use of different aryl iodides, including alkene-tethered 2-iodobenzamides and 2-(2-iodophenyl)-1H-indoles. Notably, the approach achieves simultaneous construction of both six- and seven-membered rings via sequential intramolecular carbopalladation, C-H activation, and decarboxylation.
- Zhou, Liwei,Qiao, Shujia,Zhou, Fengru,Xuchen, Xinyu,Deng, Guobo,Yang, Yuan,Liang, Yun
-
supporting information
p. 2878 - 2883
(2021/05/05)
-
- Atmosphere-Controlled Palladium-Catalyzed Divergent Decarboxylative Cyclization of 2-Iodobiphenyls and α-Oxocarboxylic Acids
-
A novel palladium-catalyzed divergent decarboxylative cyclization of 2-iodobiphenyls and α-oxocarboxylic acids utilizing the atmosphere as a controlled switch is reported. Under the protection of a nitrogen atmosphere, tribenzotropones are synthesized by a [4 + 3] decarboxylative cyclization. Employing a palladium/O2 system enables a [4 + 2] decarboxylative cyclization to assemble triphenylenes. Notably, preliminary mechanistic studies indicate that the formation of triphenylenes involves a double decarboxylation.
- Zhou, Liwei,Sun, Mingjie,Zhou, Fengru,Deng, Guobo,Yang, Yuan,Liang, Yun
-
supporting information
p. 7150 - 7155
(2021/09/18)
-
- 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)
-
- Metal-free visible light-promoted synthesis of isothiazoles: A catalytic approach for N-S bond formation from iminyl radicals under batch and flow conditions
-
A sustainable synthesis of isothiazoles has been developed using an α-amino-oxy acid auxiliary and applying photoredox catalysis. This simple strategy features mild conditions, broad scope and wide functional group tolerance representing a new enviromenta
- Alemán, José,Berton, Mateo,Cabrera-Afonso, María Jesús,Cembellín, Sara,Halima-Salem, Adnane,Maestro, M. Carmen,Marzo, Leyre,Miloudi, Abdellah
-
supporting information
p. 6792 - 6797
(2020/11/09)
-
- 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)
-
- One-Pot Asymmetric Synthesis of Alkylidene 1-Alkylindan-1-ols Using Br?nsted Acid and Palladium Catalysis
-
A one-pot catalytic enantioselective allylboration/Mizoroki-Heck reaction of 2-bromoaryl ketones has been developed for the asymmetric synthesis of 3-methyleneindanes bearing a tertiary alcohol center. Br?nsted acid-catalyzed allylboration with a chiral BINOL derivative was followed by a palladium-catalyzed Mizoroki-Heck cyclization, resulting in selective formation of the exo-alkene. This novel protocol provides a concise and scalable approach to 1-alkyl-3-methyleneindan-1-ols in high enantiomeric ratios (up to 96:4 er). The potential of these compounds as chiral building blocks was demonstrated with efficient transformation to optically active diol and amino alcohol scaffolds.
- Faggyas, Réka J.,Calder, Ewen D. D.,Wilson, Claire,Sutherland, Andrew
-
p. 11585 - 11593
(2017/11/10)
-
- 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)
-
- Nucleophile promoted gold redox catalysis with diazonium salts: C-Br, C-S and C-P bond formation through catalytic Sandmeyer coupling
-
Gold-catalyzed C-heteroatom (C-X) coupling reactions are evaluated without using sacrificial oxidants. Vital to the success of this methodology is the nucleophile-assisted activation of aryldiazonium salts, which could be an effective oxidant for converting Au(i) to Au(iii) even without the addition of an assisting ligand or photocatalyst. By accelerating the reaction kinetics to outcompete C-C homo-coupling or diazonium dediazoniation, gold-catalyzed Sandmeyer reactions were achieved with different nucleophiles, forming C-Br, C-S and C-P bonds in high yields and selectivities.
- Peng, Haihui,Cai, Rong,Xu, Chang,Chen, Hao,Shi, Xiaodong
-
p. 6190 - 6196
(2016/09/03)
-
- 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)
-
- Facile synthesis of 1-naphthols through a copper-catalyzed arylation of methyl ketones with o-bromoacetophenones
-
The coupling reactions of simple methyl ketones with o-bromoacetophenones and subsquential cyclization reactions were realized to produce a range of 1-naphthols. These cascade reactions were initiated by a rare Cu-catalyzed arylation reaction of methyl ketones with aromatic bromides.
- Lou, Zhen-Bang,Pang, Xin-Long,Chen, Chao,Wen, Li-Rong,Li, Ming
-
supporting information
p. 1231 - 1235
(2015/12/30)
-
- Substitution controlled functionalization of ortho -bromobenzylic alcohols via palladium catalysis: Synthesis of chromenes and indenols
-
An efficient domino Pd-catalyzed transformation of simple ortho-bromobenzyl tertiary alcohols to chromenes is presented. Their formation is believed to proceed via the formation of a five-membered palladacycle, which, in turn, involves in an intermolecular homocoupling with the second ortho- bromobenzyltertiary alcohol to yield the homo-biaryl bond followed by intramolecular C-O bond formation. Interestingly, when there is an allylic substituent on the benzylic carbon atom, a chemoselective switch was observed, which preferred intramolecular Heck coupling and gave indenols. Further, it has been confirmed that the tertiary alcohol functionality is indispensible to give the coupled products, whereas the use of primary/secondary benzylic alcohols furnished the simple carbonyl products via a possible reductive debromination followed by oxidation due to the availability of β-hydrogen(s).
- Mahendar, Lodi,Satyanarayana, Gedu
-
supporting information
p. 2059 - 2074
(2014/04/03)
-
- Simple, copper(I)-catalyzed oxidation of benzylic/allylic alcohols to carbonyl compounds: Synthesis of functionalized cinnamates in one pot
-
An environmentally benign [Cu(I)]-catalyzed oxidation of activated (benzylic/allylic) alcohols to the corresponding carbonyl compounds is presented. Interestingly, the reaction was also compatible with benzylic alcohols containing ortho-bromo substituents on the aromatic ring without competing with the expected intermolecular Buchwald coupling. Significantly, the catalytic system enables the synthesis of cinnamate-esters in a sequential domino one-pot fashion via oxidation followed by Wittig-Horner protocol. Copyright
- Reddy, Alavala Gopi Krishna,Mahendar, Lodi,Satyanarayana, Gedu
-
supporting information
p. 2076 - 2087
(2014/07/07)
-
- 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)
-
- Base-catalyzed synthesis of substituted indazoles under mild, transition-metal-free conditions
-
Back to basics: A transition-metal-free method developed for the synthesis of indazoles involves an inexpensive catalytic system composed of a diamine and K2CO3. Various (Z)-2-bromoacetophenone tosylhydrazones were converted into indazoles at room temperature in excellent yields (see example; Ts=p-toluenesulfonyl). The yield was improved by photoisomerization with UV light when E/Z isomeric mixtures of the starting material were used. Copyright
- Thome, Isabelle,Besson, Claire,Kleine, Tillmann,Bolm, Carsten
-
supporting information
p. 7509 - 7513
(2013/07/26)
-
- A domino palladium-catalyzed C-C and C-O bonds formation via dual O-H bond activation: Synthesis of 6,6-dialkyl-6 H -benzo[ c ]chromenes
-
An efficient Pd-catalyzed domino reaction of α,α-dialkyl-(2- bromoaryl)methanols to 6,6-dialkyl-6H-benzo[c]chromenes is presented. Their formation can be explained via a five membered Pd(II)-cycle that efficiently involves a domino homocoupling with the second molecule, β-carbon cleavage, and finally intramolecular Buchwald-Hartwig cyclization. This domino process effectively involves breaking of five σ-bonds (2C-Br, 2O-H, and a C-C) and formation of two new σ-bonds (C-C and C-O). This mechanistic pathway is unprecedented and further illustrates the power of transition metal catalysis.
- Mahendar, Lodi,Krishna, Jonnada,Gopi Krishna Reddy, Alavala,Venkat Ramulu, Bokka,Satyanarayana, Gedu
-
supporting information; experimental part
p. 628 - 631
(2012/03/11)
-
- Efficient Syntheses of Vinyl Ethers of Spiroquinol Ketals and Their High-Yield Photochemical Oxygen-to-Carbon -Shift to Spiro-Fused 2,5-Cyclohexadienones
-
An efficient route to spiroquinol vinyl ethers involves addition of a 1-lithio-2-(trimethylsilyl)acetylene-substituted benzene to the monoethyleneketal of benzoquinone followed by desilylation/cyclization of the resulting product to give vinyl ethers of spiroquinol ketals.A high-yield photochemical conversion of these vinyl ethers of spiroquinol ketals to ketals of spiro-fused 2,5-cyclohexadienones has been developed.A complication in some of these photochemical reactions is formation of secondary products from light absorbed by the product, spiro dienone ketals.This has been solved by conducting the reaction in the presence of piper ylene, which quenches the triplet-state chemistry of the product spiro dienone ketal without altering the singlet excited-state chemistry of the quinol ketal vinyl ether.The quantum yield for the photochemical -shift reaction in a methyl-substituted vinyl ether is 0.4.Finally, irradiation of quinol spiro vinyl ethers was also observed to give spiro dienones in good yields.Although the spiro dienone is absorbing light in competition with starting quinol vinyl ether in this system, a high yield of product was obtained.The unexpected photochemical stability of these spiro dienones is discussed.The chemistry reported herein establishes an efficient high-yield route to spiro-fused 2,5-cyclohexadienones and their ketals under very mild conditions.
- Swenton, John S.,Callinan, Andrew,Wang, Shaopeng
-
-
- The Ambient Temperature Ullmann Reaction and Its Application to the Total Synthesis of (+/-)-Steganacin
-
The details of a new method for preparing unsymmetrical biphenyls at room temperature by a modification of the classical Ullmann reaction are discussed.An intramolecularly coordinated organocopper reagent is treated with an aryl iodide bearing a potential coordinating ligand to form the biphenyl.Nitrogen and sulfur have been utilized as ligands and as protecting groups for carbonyls.The application of this methodology to the synthesis of the antileukemic steganacin is detailed.
- Ziegler, Frederick E.,Chliwner, Irene,Fowler, Kerry W.,Kanfer, Sheldon J.,Kuo, Stephen J.,Sinha, Nanda D.
-
p. 790 - 798
(2007/10/02)
-