<i>N</i>-Mesityl-<i>C</i>-acylketenimines: 1,5-Sigmatropic Shifts and Electrocyclization to Quinolines
作者:V. V. Ramana Rao、Belinda E. Fulloon、Paul V. Bernhardt、Rainer Koch、Curt Wentrup
DOI:10.1021/jo9722562
日期:1998.8.1
undergo a 1,5-H shift to o-quinoid imines 12/13, followed by electrocyclization to dihydroquinolines 14 (unobserved) and 15 (observed by NMR). The latter are easily oxidized to alkylquinoline-3-carboxylates or quinoline-3-carboxamides 16 by atmospheric oxygen. Ab initio calculations on model compounds 18-23 predict an energy barrier of ca. 38 kcal mol(-)(1) (161 kJ mol(-)(1)) for the 1,5-H shift in N-(o-