Liu Xigong, Zhao Changyin, Zhu Rongxiu, Liu Lei
School of School of Chemistry and Chemical Engineering, Shandong University, Jinan, 250100, P. R. China.
Angew Chem Int Ed Engl. 2021 Aug 16;60(34):18499-18503. doi: 10.1002/anie.202105594. Epub 2021 Jul 19.
The asymmetric construction of vicinal quaternary carbon stereocenters with at least one moiety in acyclic systems is a formidable challenge. We disclose a solution involving diastereo- and enantioselective oxidative 1,6-conjugate addition. The practical asymmetric cross-dehydrogenative coupling of 2,2-diarylacetonitriles and diverse α-substituted cyclic 1,3-dicarbonyls proceeds, for vicinal quaternary carbon stereocenters with one center in acyclic systems, in excellent yields and stereoselectivities. The generality of the approach is further demonstrated by the stereoselective creation of vicinal quaternary carbon stereocenters with both centers in acyclic systems using acyclic β-ketoesters as coupling partners. Computational studies elucidate the origins of both diastereo- and enantioselectivity.
在无环体系中构建具有至少一个部分的邻位季碳立体中心的不对称结构是一项艰巨的挑战。我们公开了一种涉及非对映和对映选择性氧化1,6-共轭加成的解决方案。对于在无环体系中有一个中心的邻位季碳立体中心，2,2-二芳基乙腈与各种α-取代的环状1,3-二羰基化合物进行的实用不对称交叉脱氢偶联反应，产率和立体选择性都非常出色。使用无环β-酮酯作为偶联伙伴，在无环体系中两个中心都形成邻位季碳立体中心的立体选择性反应进一步证明了该方法的通用性。计算研究阐明了非对映和对映选择性的起源。
