COPPER TRIFLATE CATALYZED REGIOSELECTIVE ALKYLATION OF PYRROLE:CONVERSION OF 2-ALKYLATED PYRROLES TO NOVEL PYRROLIZINE DERIVATIVES BY SELF-CYCLIZATION

摘要

Metal triflate catalyzed addition reaction of pyrrole to methyl 2-oxo-4-phenylbut-3-enoate and substituted derivatives generated the related novel alkylated pyrroles regioselectively at C(2) of pyrrole.Among the studied metal triflates,Cu(OTfh was found to be more effective in the addition reaction.The synthesized methyl 2-oxo-4-phenyl-4-(1H-pyrrole-2-yl)butanoate esters underwent self-cyclization by heating and yielded the corresponding methyl 3-hydroxy-1-phenyl-2,3-dihydro-1H-pyrrolizine-3-carboxylate and substituted derivatives.This reaction procedure allowed easy access to pyrrolizine structure in mild reaction conditions.