Enantioselective Alkylation of 2‐Oxindoles Catalyzed by a Bifunctional Phase‐Transfer Catalyst: Synthesis of (−)‐Debromoflustramine B

A new bifunctional phase‐transfer catalyst that employs hydrogen bonding as a control element was developed to promote efficient enantioselective S N 2 reactions for the construction all‐carbon quaternary stereocenters in high yield and excellent enantioselectivity (up to 97 % ee ) utilizing the alkylation of a malleable oxindole substrate. The utility of the methodology was demonstrated through a concise and highly enantioselective synthesis of (−)‐debromoflustramine B.