Pentanidium-Catalyzed Direct Assembly of Vicinal All-Carbon Quaternary Stereocenters through C(sp^(3))–C(sp^(3))Bond Formation

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 themost 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.