Fused Pyrrolo[2,3-d]pyrimidines (7-Deazapurines) by Palladium-Catalyzed Direct N–H and C–H Arylation Reactions

Abstract

Palladium-catalyzed intramolecular direct C–H arylations for the synthesis of hitherto unknown fused hetero systems containing an incorporated pyrrolo[2,3-d]pyrimidine scaffold are described. Pyrimido[5′,4′:4,5]pyrrolo[2,1-a]isoindoles were synthesized from 2,4-di­arylpyrrolo[2,3-d]pyrimidines and o-bromobenzyl bromides by using a cascade N-benzylation/C–H arylation reaction sequence. A series of pyrimido[5′,4′:4,5]pyrrolo[1,2-f]phenanthridines were successfully assembled via a domino process involving the palladium-catalyzed direct double C–H arylation reactions of 2,4,7-triarylpyrrolo[2,3-d]pyrimidines with o-bromoiodobenzenes.