作者:Diego Armesto、Ana Ramos、Maria J. Ortiz、Maria J. Mancheño、Elena P. Mayoral
DOI:10.1002/recl.19951141116
日期:——
Previously, β, γ-unsaturated oximes were thought to be photochemically unreactive. The present study reports the first three examples of photocyclization of β,γ-unsaturated ketoximes to yield 4,5-dihydroisoxazole derivatives. Typically, acetophenone-sensitized irradiation of 3,3-dimethyl-5,5-diphenylpent-4-en-2-one oxime (2) affords 5-(diphenylmethyl)-3,4,4-trimethyl-4,5-dihydroisoxazole (3) in 38%
以前,β,γ-不饱和肟被认为是光化学反应性的。本研究报告了β,γ-不饱和酮肟光环化以生成4,5-二氢异恶唑衍生物的前三个例子。通常,对3,3-二甲基-5,5-二苯基戊-4-烯-2-酮肟(2)进行苯乙酮敏化辐照可得到5-(二苯基甲基)-3,4,4-三甲基-4,5-二氢异恶唑(3)产率为38%。提出了单电子转移(SET)机制来解决环化问题。