Zhong-Quan Liu

Copper- and Iron-Catalyzed Decarboxylative Tri- and Difluoromethylation of α,β-Unsaturated Carboxylic Acids with CF3SO2Na and (CF2HSO2)2Zn via a Radical Process

A copper-catalyzed decarboxylative trifluoromethylation of various α,β-unsaturated carboxylic acids by using a stable and inexpensive solid, sodium trifluoromethanesulfinate (CF(3)SO(2)Na, Langlois reagent), was developed. In addition, an iron-catalyzed difluoromethylation of aryl-substituted acrylic acids by using zinc difluoromethanesulfinate (DFMS, (CF(2)HSO(2))(2)Zn, Baran reagent) via a similar radical process was also achieved.

Free-Radical Cascade Alkylarylation of Alkenes with Simple Alkanes: Highly Efficient Access to Oxindoles via Selective (sp3)C–H and (sp2)C–H Bond Functionalization

A copper-catalyzed alkylarylation of alkenes with simple alkanes was achieved, which not only provided an efficient method to prepare various alkyl-substituted oxindoles, but also represented a novel strategy for selective sp(3) C-H functionalization/C-C bond formation via a free-radical cascade process. Additionally, selective activation of unactivated (sp(3))C-H and (sp(2))C-H bonds by one single step is achieved in this system, which would also provide a novel strategy for raising efficiency in C-H bond functionalization.

Copper-catalyzed decarboxylative alkenylation of sp3 C–H bonds with cinnamic acids via a radical process

A copper-catalyzed decarboxylative coupling of vinylic carboxylic acids with simple alcohols, ethers, and hydrocarbons was achieved. In the past decades, most of the sp3 α-C–H activation/C–C bond formation reactions proceeded via an addition of a α-hydroxy carbon-centered radical to heterocycles, alkenes, and alkynes. The present system exhibits a novel pathway for the functionalization of various sp3 C–H bonds via radical addition–elimination of aryl-substituted vinyl carboxylic acids. This strategy allows for rapid and selective access to a variety of (E)-alkenes such as allylic alcohols, allylic ethers, and substituted styrenes. In addition, this procedure could be scaled up to gram level, which would be useful to prepare natural products and pharmaceuticals that contain chromene and its derivatives.

A Free Radical Cascade Cyclization of Isocyanides with Simple Alkanes and Alcohols

A copper-catalyzed free-radical cascade cyclization of isocyanides with simple alkanes and alcohols was developed, which allowed convenient access to various alkyl-substituted phenanthridines.

A Free-Radical Cascade Trifluoromethylation/Cyclization of N-Arylmethacrylamides and Enynes with Sodium Trifluoromethanesulfinate and Iodine Pentoxide

An I(2)O(5)-promoted free-radical cascade trifluoromethylation/cyclization of a broad range of N-arylmethacrylamides and enynes with sodium trifluoromethanesulfinate in aqueous medium has been achieved. This strategy allows highly selective access to a variety of CF(3)-containing oxindoles and pyrrolidines. Electron spin resonance (ESR) studies indicate that atom-transfer processes are involved in this system.

Free-Radical-Initiated Coupling Reaction of Alcohols and Alkynes: Not C−O but C−C Bond Formation

This work demonstrates an efficient method to prepare allylic alcohols via direct C-C bond formation using electron-rich alkynes and aliphatic alcohols initiated by tert-butyl hydroperoxide.

Iodotrifluoromethylation of Alkenes and Alkynes with Sodium Trifluoromethanesulfinate and Iodine Pentoxide

A scalable, selective, and operationally easy iodotrifluoromethylation of a wide range of alkenes and alkynes by using two simple and safe solids, sodium trifluoromethanesulfinate and iodine pentoxide, in aqueous medium has been developed. Mechanistic studies confirm that free-radical processes are involved in this system since the key radical intermediates such as CF(3) and β-CF(3) alkyl radicals have been clearly detected by spin trapping and electron spin resonance.

A free-radical cascade methylation/cyclization of N-arylacrylamides and isocyanides with dicumyl peroxide.

A free-radical cascade methylation/cyclization of a wide range of N-arylacrylamides and isocyanides is demonstrated by using dicumyl peroxide as the methylating reagent, which provides a convenient and selective access to various methylated N-heterocycles such as oxindoles and phenanthridines.

Pd-Catalyzed Olefination of Furans and Thiophenes with Allyl Esters

A direct Pd(II)-catalyzed olefination of furans and thiophenes with allyl esters is demonstrated. Under the typical conditions, the dehydrogenative Heck coupling reactions of heteroarenes with allylic esters proceeded via a β-H elimination rather than a β-OAc elimination to give the corresponding γ-substituted allylic esters.

Pd-Catalyzed Olefination of Perfluoroarenes with Allyl Esters

An efficient Pd(II)-catalyzed direct olefination of perfluoroarenes with allyl esters is demonstrated. Under the typical conditions, the coupling reaction of fluorinated-arenes with allylic esters proceeded via a β-H elimination rather than a β-OAc elimination to give the corresponding γ-substituted allylic esters.