摘要
赤霉素(gibberellins)是一类重要的植物生长激素,应用广泛,它们的合成反应研究颇受重视.Adam等较系统地探讨了其光化学反应,例如光催化芳构化、光致环加成以及Norrish Ⅰ型反应等.最近周维善应用Sharpless试剂改良氧化法于赤霉酸衍生物的合成.但是迄今仍无有关赤霉素类光氧化反应的报道.鉴于多种重要生物分子的光动态作用(photodynamic action)所引起的光氧化损害在理论和应用上的重要意义。
Methyl gibberellate (MG) undergoes sensitized photooxidation in solution, leading to the formation of ene-reaction products, 15-enol 1 and 15-enal 2. Among sensitizers, 9,10-dicyanoanthracene (DCA) and lumiflavin (LF) show higher reactivities on the reaction. A singlet oxygen mechanism is proposed based on several evidences. The reaction exhibites high chemoselectivity, i. e. the title reaction occurs exclusively at 16-exo double bond but no reaction the ring 1-double bond. This is rationalized in terms of ring-strain enhanced reactivity of the exo double bond towards electrophilic ~1O_2 as well as the neighbouring group participation of 13-hydroxy on the exo double bond.The photooxidation method employed in this work may provide a new way for the symthesis of oxygln containing derives with shiftid exo double bend in polyoyclic system.
出处
《化学学报》
SCIE
CAS
CSCD
北大核心
1991年第2期205-208,共4页
Acta Chimica Sinica
基金
兰州大学应用有机化学国家实验室开放基金
