Studies on Thermal Reactivity of β-(1,2-Allenyl)butenolides and 2-Allyl-3-allenylcyclohex-2-enones
作者:Zhenhua Gu、Shengming Ma
DOI:10.1002/chem.200701171
日期:2008.3.7
A series of thermal pericyclic reactions of beta-allenylfuranones have been studied. It was observed that beta-allenylfuranones would undergo 1,5-hydrogen shift to afford a new type of trienes upon heating. Due to their high reactivity, these trienes would undergo subsequent pericyclic reactions based on the nature of the substituent group R: When R is an alkyl group, the intermediate 4a or 4b would
β-烯基呋喃酮的一系列热周环反应已得到研究。观察到,加热时β-烯基呋喃酮会发生1,5-氢转移,以提供新型的三烯。由于它们的高反应性,这些三烯会根据取代基R的性质进行随后的周环反应:当R为烷基时,中间体4a或4b会进一步发生1,7氢转移,从而提供更稳定的共轭三烯3; 在R为苯基或环丙基的情况下,抑制了1,7-氢转移,并且4-型共轭三烯将通过6个π-电环化反应形成六元环5。有趣的是,将另一个C = C双键引入三烯中间体(R = CH = CH2,则18型中间体将进行8π电环化反应,形成一个八元环。用2-烯丙基-3-烯丙基环己基-2-烯酮也观察到了这种转化。氘标记机理的研究表明,1的烯基部分上的烷基通过18 A,20 A和29 A之间的1,7氢转移参与了异构化过程。