The stereoselective construction of vicinal all-carbon quaternary stereocenters has long been a formidable synthetic challenge. Direct asymmetric coupling of a tertiary carbon nucleophile with a tertiary carbon electrophile is the most straightforward approach, but it is sterically and energetically disfavored. Herein, we describe a catalytic asymmetric substitution, where racemic tertiary bromides coupled directly with racemic secondary or tertiary carbanion, creating a series of congested C(sp³)–C(sp³) bonds, including isolated all-carbon quaternary stereocenters, vicinal tertiary/all-carbon quaternary stereocenters and vicinal all-carbon quaternary stereocenters. Using pentanidium as a catalyst, this double stereoconvergent process afforded substituted products in good enantioselectivities and diastereoselectivities.

邻位全碳四元立体中心的立体选择性构建长期以来一直是一项艰巨的合成挑战。叔碳亲核试剂与叔碳亲电试剂的直接不对称偶联是最直接的方法，但在空间和能量上都不受欢迎。在此，我们描述了一种催化不对称取代，其中外消旋叔溴化物直接与外消旋二级或三级碳负离子偶联，产生一系列拥挤的 C(sp ³ )–C(sp ³) 键，包括孤立的全碳四元立体中心、邻位叔/全碳四元立体中心和邻位全碳四元立体中心。使用戊作为催化剂，这种双立体会聚过程提供了具有良好对映选择性和非对映选择性的取代产物。