Nickel-Catalyzed Enantio- and Diastereoconvergent Allenylation of Alkyl Electrophiles: Concurrent Generation of Point and Axial Chirality

由于大多数现代药物都要求以光学纯形式生产，因此对允许安装一个或多个具有几乎完全立体控制的手性中心（包括绝对构型）的合成方法的需求很大。在现代不对称催化领域，控制由外消旋偶联伙伴（邻体中心）形成的新键的两个碳中心的立体化学是一项具有挑战性的任务。在此，本文提出了一个有前景的概念，即在手性镍催化剂的存在下，前手性和外消旋底物可以有效地偶联，产生具有两个立体中心的对映体富集产物，其中一个是三碳轴向手性。该方法将提供一种简单实用的方法，利用地球上丰富的金属催化剂，一步合成多种具有双立体中心的高附加值生物活性化合物，最终开辟不对称合成的新途径。

Since the majority of the contemporary pharmaceuticals are required to be produced in optically pure forms, the synthetic methods that allow the installation of one or more chiral centres with nearly complete stereocontrol, including absolute configuration, are in great demand. In the field of modern asymmetric catalysis, controlling the stereochemistry at both carbon centres of a newly formed bond originating from racemic coupling partners (vicinal stereocentres) is a challenging task. Herein, this proposal outlines a promising concept where a prochiral and a racemic substrate could be efficiently coupled in the presence of a chiral nickel catalyst to produce enantioenriched products with two stereocenters among which one of them is three-carbon axially chiral. The methodology would offer a straightforward and practical way to synthesize various value-added, bioactive compounds bearing double stereocentres in a single step by utilizing earth-abundant metal catalyst, eventually opening up new passages in asymmetric synthesis.