Intramolecular Ene Reactions. Stereo- and Enantioselective Synthesis of Spirolactams through Thermolysis of Enamino Carboxamides
作者:Janine Cossy、Abdelrrahim Bouzide、Michel Pfau
DOI:10.1021/jo970257o
日期:1997.10.1
thermal rearrangement of tertiary and secondary enamino carboxamides has been developed. The enamine group of an enamino carboxamide, in which no electron-withdrawing group is present in the enophile, can be involved in the ene reaction and the enamino carboxamide can be transformed into enamino or imino spirolactams. In the case of secondary carboxamido enamines, the diastereoselectivity is higher than 98%
Substituted lactams and spirolactams were obtained by Mn(III)-induced radical cyclization of unsaturated beta -keto carboxamides. Treatment of the corresponding tertiary enamines under similar reaction conditions and in the presence of K2CO3 afforded the same cyclized products but with inversion of diastereoselectivity. The oxidation of optically pure secondary enamines leads to diastereomeric spirolactams in an approximately 3:1 ratio.
Stereoselective formation of spirolactams by intramolecular ene reaction
作者:J. Cossy、A. Bouzide
DOI:10.1016/s0040-4039(00)92226-3
日期:1992.4
A new and facile access to spirolactams based on the thermal rearrangements of N,N-unsaturated dialkyl-β-ketoamides and N,N-unsaturated dialkyl enaminoamides has been developed.