Various substituted cyclohexenes related to α-cyclocitral have been prepared using the heterodiene cycloadditions of 2-formyl-4,4-dimethyl-2-cyclohexen-1-one 4 with ketene acetals as the pivotal step. The key intermediates are accessible in homochiral form via an auxiliary-based sequence in which a C2-symmetric ketene acetal derived from 1,2-bis(2-methylphenyl)ethane-1,2-diol 2a serves as the 2π component
使用2-甲酰基-4,4-二甲基-
2-环己烯-1-酮4与烯酮
缩醛的杂二烯环加成作为关键步骤,已经制备了与α-环
柠檬醛有关的各种取代的
环己烯。可以通过基于辅助的序列以同手性形式获得关键中间体,其中衍生自1,2-双(2-甲基苯基)
乙烷-1,2
-二醇2a的C 2对称烯酮
缩醛用作2π组分。可以以光学纯的形式回收二醇2a。