Asymmetric Retro-Claisen Reaction by Chiral Primary Amine Catalysis
作者:Yunbo Zhu、Long Zhang、Sanzhong Luo
DOI:10.1021/jacs.6b00627
日期:2016.3.30
The communication describes an enamine-based asymmetric retro-Claisen reaction of β-diketones by primaryamine catalysis. The reaction proceeds via a sequence of stereoselective C-C formation, C-C cleavage, and a highly stereospecific enamine protonation to afford chiral α-alkylated ketones or macrolides with high yields and enantioselectivities. A detailed mechanism was explored on the basis of experimental
该通讯描述了伯胺催化下 β-二酮的基于烯胺的不对称逆克莱森反应。该反应通过一系列立体选择性 CC 形成、CC 裂解和高度立体有择的烯胺质子化进行,以提供具有高产率和对映选择性的手性 α-烷基化酮或大环内酯。在实验证据和计算研究的基础上探索了详细的机制,以解释观察到的立体控制。
7-MEMBERED FUSED HETEROCYCLES AND METHODS OF THEIR SYNTHESIS
申请人:Northwestern University
公开号:US20150065703A1
公开(公告)日:2015-03-05
Disclosed are a new method for synthesizing 7-membered fused heterocycles and compounds synthesized by the new method. The method involves a dual activation strategy using an N-heterocyclic carbene catalyst as a first Lewis base and another second Lewis base. Compounds synthesized by the disclosed method may include new benzoxopinone compounds, as well as benzoxepane compounds and benzoazepinone compounds that optionally may be derived from the disclosed benzoxopinone compounds.
Catalytic Asymmetric Synthesis of Chiral Dihydrobenzofurans through a Formal [4+1] Annulation Reaction of Sulfur Ylides and In Situ Generated<i>ortho</i>-Quinone Methides
作者:Qing-Qing Yang、Wen-Jing Xiao
DOI:10.1002/ejoc.201601186
日期:2017.1.10
The first example of a catalytic asymmetric formal [4+1] annulation reaction between sulfur ylides and in situ generated ortho-quinone methides (o-QMs) is reported in this work. A C2-symmetric chiral urea was identified to be the best H-bonding catalyst, affording a wide range of chiral 2,3-dihydrobenzofurans in high yields and moderate enantioselectivities [70–98 % yields, up to 89:11 e.r. (enantiomeric
在这项工作中报道了硫叶立德与原位生成的邻醌甲基化物 (o-QMs) 之间的催化不对称形式 [4+1] 环化反应的第一个例子。一种 C2 对称手性尿素被认为是最好的 H 键合催化剂,可提供范围广泛的手性 2,3-二氢苯并呋喃,收率高,对映选择性适中 [70–98% 收率,高达 89:11 er )]。