Role of cations and confinement in asymmetric photochemistry: enantio- and diastereo-selective photocyclization of tropolone derivatives within zeolites
作者:Abraham Joy、Lakshmi S. Kaanumalle、V. Ramamurthy
DOI:10.1039/b504865f
日期:——
induction. Tropolone derivatives, upon irradiation undergo 4pi-electron electrocyclization to yield a bicyclic product and a rearranged product. Enantiomeric excess up to 68% has been achieved in the cyclized product. In systems where a chiral inductor has been covalently linked, diastereomeric excess as high as 88% has been achieved within a zeolite while the same system in solution gave 10%.
已经使用对苯二酚的光化学作为模型探索了光化学反应中的不对称诱导。已经研究了三种方法:手性感应剂,手性辅助剂和[手性感应剂+手性辅助剂]。这三种方法在沸石中均具有出色的不对称诱导性,而在溶液中则极少或为零。在对讲机上显示的结果清楚地说明了一个充满阳离子的密闭空间可能对不对称感应产生的显着影响。Tropolone衍生物在辐照下会经历4π电子电环化,生成双环产物和重排产物。在环化产物中,对映体过量高达68%。在已将手性电感器共价连接的系统中,