Facile synthesis of 2-methylenecyclobutanones via Ca(OH)<sub>2</sub>-catalyzed direct condensation of cyclobutanone with aldehydes and (PhSe)<sub>2</sub>-catalyzed Baeyer–Villiger oxidation to 4-methylenebutanolides
(2-MCBones), used to be difficult to access, but can now be easily achieved by a green and stereospecific Ca(OH)2-catalyzed direct and simple aldol condensation of cyclobutanone and aldehydes under mild conditions. The obtained (E)-2-MCBones should be a class of potentially useful building blocks in synthesis as they could readily undergo an interesting (PhSe)2-catalyzed Baeyer–Villiger (BV) oxidation
2-亚甲基环丁酮(2-MCBones)过去很难获得,但现在可以通过在绿色和立体定向Ca(OH)2催化下在温和条件下环丁酮和醛的直接简单的羟醛缩合直接实现。所获得的(E)-2-MCBones应该是一类在合成中潜在有用的结构单元,因为它们在室温下很容易通过H 2 O 2进行有趣的(PhSe)2催化的Bayerer -Villiger(BV)氧化而得到通用的4-亚甲基丁醇化物。机理研究表明,BV反应最有可能通过苯硒代过氧苯甲酸酐[PhSe(O)O] 2的初步形成而进行。O然后转化为苯硒酸过氧酸PhSe(O)OOH作为活性氧化剂,然后将其选择性添加到2-MCBones的C O键中,然后进行选择性的C-C键裂解和重排,得到4-亚甲基丁醇化物。