Photocyclization of a Bichromophoric Phenol/Olefin System Substituted at the Methylene Spacer − Zwitterions versus H-Bridged Intermediates in the Excited State Proton Transfer
作者:M. Consuelo Jiménez、Miguel A. Miranda、Rosa Tormos、Salvador Gil
DOI:10.1002/1099-0690(20021)2002:2<297::aid-ejoc297>3.0.co;2-7
日期:2002.1
Photolysis of (E)- and (Z)-2-(1-ethyl-3-phenylpropenyl)phenol (1 and 2) under a variety of conditions produces a mixture of dihydrobenzopyrans 3 and 4, dihydrobenzofuran 5, cyclopropanes 6 and 7, and rearranged olefin 8. Acidic treatment of 1 and 2 gives a mixture of the six-membered ring products 3 and 4. Remarkable differences, associated with the nature of the precursor and the reaction conditions
(E)- 和 (Z)-2-(1-乙基-3-苯基丙烯基) 苯酚 (1 和 2) 在各种条件下的光解产生二氢苯并吡喃 3 和 4、二氢苯并呋喃 5、环丙烷 6 和 7 的混合物,和重排烯烃 8. 1 和 2 的酸处理得到六元环产物 3 和 4 的混合物。在环化的区域化学和反应中观察到与前体性质和反应条件有关的显着差异二氢苯并吡喃的立体化学(3/4 比例)。这表明 H 桥接中间体,而不是完全两性离子物种,作为光环化产物的直接前体。