摘要:
4-(1,5-Dialkynyl)-4-methoxycyclobutenones 1 were shown to undergo a unique rearrangement to annelated spiroepoxides 6 upon thermolysis in toluene. The 4-hydroxy analogs also ring expand giving either quinones 13 or 14 as a function of the reaction solution concentration. This concentration dependence provides evidence for further mechanistic details of the general quinone synthesis stemming from 4-alkynyl-4-hydroxycyclobutenones.