Cobalt-catalyzed annulation of styrenes with α-bromoacetic acids
作者:Tung T. Nguyen、Bao H. T. Ngo、Huy X. Le、Linh N. P. Vu、Tuong A. To、Anh N. Q. Phan、Nam T. S. Phan
DOI:10.1039/d0ra09588e
日期:——
We report a method for addition of α-bromophenylacetic acids to vinyl CC bonds in styrenes to afford γ-lactones. Reactions employed a simple cobalt catalyst Co(NO3)2·6H2O in the presence of dipivaloylmethane (dpm) ligand. Many functionalities including halogen, ester, and nitro groups were compatible with reaction conditions. If α-bromoesters were used, vinylacetates were the major products.
我们报告了一种将 α-溴苯乙酸添加到苯乙烯中的乙烯基 C C 键以提供 γ-内酯的方法。在二戊酰甲烷 (dpm) 配体存在下,反应使用简单的钴催化剂 Co(NO 3 ) 2 ·6H 2 O。许多官能团,包括卤素、酯和硝基,都与反应条件相容。如果使用 α-溴代酯,醋酸乙烯酯是主要产品。
Palladium-catalyzed cross-coupling of enamides with sterically hindered α-bromocarbonyls
Palladium-catalyzed intermolecular alkylation of enamides with [small alpha]-bromo carbonyls was developed. Under mild reaction conditions, various cyclic and acyclic enamides reacted well with [small alpha]-bromo carbonyls to afford the corresponding multi-substituted alkene...
Organo-photoredox-Catalyzed Atom-Transfer Radical Substitution of Alkenes with α-Carbonyl Alkyl Halides
作者:Goki Hirata、Taisei Shimada、Takashi Nishikata
DOI:10.1021/acs.orglett.0c03359
日期:2020.11.20
(ATRS) and carboesterification reaction of alkenes with alkyl halides has been developed using PTH as the organo-photoredox catalyst. Two types of products were obtained, depending on the additive and solvent used during the reaction. Primary, secondary, and tertiary alkyl halides reacted to give the ATRS products. This protocol has several advantages: it requires mild reaction conditions and a low catalyst
Nickel-Catalyzed Heck-Type Alkenylation of Secondary and Tertiary α-Carbonyl Alkyl Bromides
作者:Chao Liu、Shan Tang、Dong Liu、Jiwen Yuan、Liwei Zheng、Lingkui Meng、Aiwen Lei
DOI:10.1002/anie.201108350
日期:2012.4.10
Ni made it! A novel Heck‐type reaction of secondary and tertiary α‐carbonyl alkyl bromides, most likely involving a radical process, was achieved through the use of a nickel catalyst. Various substituted styrenes and 1,1‐diaryl alkenes were utilized as substrates to easily construct α‐alkenyl carbonyl compounds with tertiary or quaternary carbon centers. A catalytic cycle involving NiI/NiII is proposed
倪做到了!通过使用镍催化剂,实现了仲和叔α-羰基烷基溴化物的新型Heck型反应,最有可能涉及自由基过程。各种取代的苯乙烯和1,1-二芳基烯烃被用作底物,以轻松构建具有叔碳或季碳中心的α-烯基羰基化合物。基于我们的实验结果,提出了涉及Ni I / Ni II的催化循环。EWG =吸电子基团。
Copper-Catalyzed Alkylation of Silyl Enol Ethers with Sterically Hindered α-Bromocarbonyls: Access to the Histamine H<sub>3</sub> Receptor Antagonist
作者:Dengke Li
DOI:10.1021/acs.joc.0c02277
日期:2021.1.1
A general and efficient copper-catalyzed alkylation of silyl enolethers with functionalized alkyl bromides has been developed for the synthesis of the sterically hindered γ-ketoesters. The transformation was induced through C(sp3)-halogen activation of commercially available sterically hindered alkyl bromides under mild conditions in good results. The strategy could be used for the synthesis of biologically