Reactions of 1,5-π-cyclization of gem-difluoro-substituted azomethine ylides involving an aromatic ring
摘要:
Reactions of N-(5-R-furan-2-ylmethylidene)anilines with difluorocarbene proceeds through intermediate azomethine ylides suffering 1,5-pi-cyclization to yield 6,6-difluorocyclopropa[b]furo[2,3-c]pyrrole and/or 4,4,6,6-tetrafluorocyclopropa[b]furo[2,3-c]pyrrole. The heating of these compounds without solvent resulted in high yields of 2,5-disubstituted 7-fluoro-4,5-dihydrofuro[3,2-c]pyridin-4(5H)-ones.