Photocyclization reactions. Part<b>5</b>. Synthesis of dihydrobenzofuranols using photocyclization of 2-alkoxybenzophenones and ethyl 2-benzoylphenoxyacetates
作者:Essam Mohamed Sharshira、Satoru Shimada、Mutsuo Okamura、Eietsu Hasegawa、Takaaki Horaguchi
DOI:10.1002/jhet.5570330641
日期:1996.11
Photocyclization reactions were carried out on 2-alkoxybenzophenones 1a-h and ethyl 2-benzoylphenoxyacetates 2a-e in acetonitrile. Irradiation of 1a-h gave dihydrobenzofuranols 4a-h in 68–84% yields. Similarly, irradiation of 2a-e afforded dihydrobenzofuranols 8a-e in 72–75% yields. Ethyl acrylates 9b-c were also produced in 6–8% yields from photoreactions of 2b-c. Substituent effects on cyclization
对2-烷氧基二苯甲酮1a-h和2-苯甲酰基苯氧基乙酸乙酯2a - e在乙腈中进行光环化反应。辐照1a-h可获得二氢苯并呋喃醇4a-h,产率为68-84%。同样,辐照2a-e可获得二氢苯并呋喃醇8a-e,产率为72-75%。丙烯酸乙酯9b-c也是由2b-c的光反应产生的,产率为6-8%。讨论了取代基对1,5-双自由基中间体环化和反应途径的影响。二苯甲酮是通过光环化制备二氢苯并呋喃醇的有用化合物。