Accessing New 5‐α‐(3,3‐Disubstituted Oxindole)‐Benzylamine Derivatives from Isatin: Stereoselective Organocatalytic Three Component Petasis Reaction

Abstract

A one‐step, three‐component Petasis reaction of isatin derived 5‐arylboronate‐3‐substituted oxindole derivatives with salicylaldehydes and secondary amines affords new enantiomerically pure structurally diverse 5‐α‐(3‐substituted‐oxindole)‐benzylamine derivatives. The reaction shows good substrate and reagent scope affording the products with good to excellent yields (up to >99 % yield) and enantioselectivities (up to 99 % ee) using cheap and readily available (R)‐BINOL as the organocatalyst. A diastereoselective version of the reaction was also developed where moderate yields (37 to 55 % yield), excellent enantioselectivities (up to 99 % ee) and good diastereoselectivities (up to 86 % de) were obtained for new 5‐α‐(3‐hydroxy‐oxindole)‐benzylamine derivatives, having two stereocenters. The reaction is also feasible on gram‐scale.