Alkylidene-2H-pyrans by thermal electrocyclic ring closure of (2Z)-divinylallenals
作者:Angel R. de Lera、Alicia Torrado、José García Rey、Susana López
DOI:10.1016/s0040-4039(97)01746-2
日期:1997.10
Electrocyclicringclosure of (2Z)-divinylallenals 8 (including the retroretinal derivative 8a), afforded the corresponding alkylidene-2H-pyrans, under very mild conditions (25 °C, 48 h). Initially, an equilibrium between 8a and the kinetic product was observed, but this gradually reverted to the thermodynamically more stable .