Ready Access to Alkylidenecyclopentenones by Nazarov Cyclization/β-Elimination of 2-Hydroxyalkyl-1,4-dien-3-ones
作者:Owen Scadeng、F. G. West
DOI:10.1002/ejoc.201301537
日期:2014.3
followed by deprotonation of the resulting cyclopentenyl cation, and β-elimination of the exocyclic hydroxy group to form alkylidenecyclopentenones in moderate yield. The deprotonation step occurs with complete regioselectivity opposite to the hydroxyalkyl substituent, with preferential introduction of an endocyclic olefin. The transformation is tolerant of a variety of substituents and occurs under relatively
带有 α-羟烷基取代基的交叉共轭二烯酮很容易进行 Nazarov 环化,然后将所得环戊烯基阳离子去质子化,并β-消除环外羟基,以中等产率形成亚烷基环戊烯酮。去质子化步骤以与羟烷基取代基相反的完全区域选择性发生,优先引入内环烯烃。这种转变可以容忍多种取代基,并且在相对温和的条件下发生。