Palladium‐Catalysed Norbornene‐Mediated Regioselective Direct C−H Glycosylation of Free (N−H) Pyrrole Derivatives

Abstract

A palladium‐catalyzed norbornene‐mediated regioselective direct C−H glycosylation of free N‐H pyrrole and electron‐deficient pyrrole derivatives has been developed. The reaction involves the use of a PdII catalyst and norbornene as a transpositional co‐catalyst, in which a pyrrole‐ and norbornyl‐fused palladaheterocycle forms as the key intermediate. The 2‐substituted pyrroles, and other 2,3‐disubstituted pyrroles underwent the selective C5 glycosylation. This reaction is compatible with a various types of glycosyl chlorides including D‐mannose, L‐rhamnose, D‐mannofuranose, and D‐ribofuranose. The viability of this strategy is showed by gram‐scale, various synthetic transformation and functionalization.