An efficientenantioselectiveinsertion of α-diazoesters and α-diazoketones into O–H bonds of carboxylic acids was realized by the use of Rh2(OAc)4 and a chiral guanidine. Optically active α-acyloxy carbonyl compounds were generated under mild reaction conditions in high yields (up to 99%) and good enantioselectivities (up to 97.5:2.5 er).
talyzed C−C bond functionalization of arylallyl alcohols using donor‐acceptor carbenes is presented. The allylic hydroxyl group is found to assist the product formation by neighboring group participation providing a clue towards mechanistic understanding. This method can also be employed to effect homologation of allylalcohols to homoallyl alcohols. Overall, this metal‐free transformation presents
Catalyst-free, visible-light-promoted S–H insertion reaction between thiols and α-diazoesters
作者:Jingya Yang、Ganggang Wang、Shuwen Chen、Ben Ma、Hongyan Zhou、Menghui Song、Cai Liu、Congde Huo
DOI:10.1039/d0ob02006k
日期:——
A visible-light-promoted S–H insertion reaction betweenthiols and α-diazoesters was developed. The reaction proceeded smoothly at room temperature with a broad substrate scope, affording various thioethers in moderate to excellent yields. The catalyst- and additive-free nature, sustainable energy source and mild reaction conditions make this strategy more eco-friendly.
The development of an efficient method for the site‐selective substitution of unprotected phenols has long been considered as an attractive but challenging task. Herein, we describe a highly chemo‐ and ortho‐selective substitution reaction of phenols with α‐aryl α‐diazoacetates with commercially available (C6F5)3B as the catalyst. This reaction proceeds under simple and mild conditions with high efficiency
长期以来,人们一直认为开发一种有效的方法来对未保护的酚进行位点选择性取代是一项有吸引力的任务,但具有挑战性。本文中,我们描述了苯酚与α-芳基α-重氮乙酸酯的高度化学和邻位选择性取代反应,并以市售(C 6 F 5)3 B作为催化剂。该反应在简单温和的条件下以高效率进行,它具有广泛的底物范围,并且易于扩大规模。
Copper-Catalyzed Tandem Cross-Coupling and Alkynylogous Aldol Reaction: Access to Chiral Exocyclic α-Allenols
作者:Guangyang Xu、Zhen Wang、Ying Shao、Jiangtao Sun
DOI:10.1021/acs.orglett.1c01712
日期:2021.7.2
tandem cross-coupling/alkynylogous aldol reaction has been developed. The tetrasubstituted allenoates containing both central and axial chirality have been obtained in moderate to good yields and excellent enantio- and diastereoselectivity. Distinct from the previous use of Cu(I) salts, this protocol features the use of copper(II) salts as a catalytic precursor in this asymmetric cross-coupling reaction
已经开发了对映选择性铜催化串联交叉偶联/炔醇醛醇反应。已经以中等至良好的产率和优异的对映选择性和非对映选择性获得了同时含有中心手性和轴向手性的四取代烯丙酸酯。与之前使用的铜 (I) 盐不同, 该协议的特点是在这种不对称交叉偶联反应中使用铜 (II) 盐作为催化前体。