Organocatalytic Enantioselective Construction of Axially Chiral Tetrasubstituted Allenes via 1,6‐Addition of Alkynyl Indole Imine Methides with 2‐Substituted Indoles

Abstract An organocatalytic construction of axially chiral tetrasubstituted allenes featuring indole skeletons has been established. With the aid of chiral phosphoric acid, alkynyl indole imine methides were formed in situ from α‐(3‐indolyl) propargylic alcohols, followed by the asymmetric 1,6‐conjugate addition with 2‐substituted indoles, furnishing axially chiral indole‐containing tetrasubstituted allenes in generally high yields and enantioselectivities.