The stereo- and regio-specific formation of 11-oxatetracyclo[6.2.1.0.0]undeca-5,9-dienes by the substituent-directed photocycloaddition of furan to the benzene ring
作者:Andrew Gilbert、Paul W. Rodwell
DOI:10.1039/p19900000931
日期:——
Furan undergoes specific 2,5–2′,6′(meta)-photocycloaddition to benzonitrile, the toluonitriles, phenylacetylene, and 1-phenylpropyne. 2-Phenylpropene yields exclusively a [2π+ 2π] cycloadduct with furan whereas both types of addition occur with styrene. In contrast, 1,4–2′,5′(para)-photocycloaddition is the sole or principal reaction from 254 nm irradiation of isoprene, 2,3-dimethylbuta-1,3-diene,
呋喃会经历特定的2,5–2',6'(间位)-光环加成反应,生成苯甲腈,甲苯腈,苯乙炔和1-苯基丙炔。2-苯基丙烯的产率仅仅一个[2 π + 2 π ]环加成物与呋喃而这两种类型的另外的与苯乙烯发生。相比之下,1,4–2',5'(对)-光环加成是254 nm异戊二烯,2,3-二甲基丁1,3-二烯或2,3-二甲氧基丁1的唯一或主要反应,3-二烯与苄腈; 仅具有固定的顺式-1,3-二烯,1,2-二亚甲基环己烷,才形成大量的间环加合物。对元的区域和立体化学的控制关于-环加成,在加成和次级轨道相互作用的方法上,对电子激发的芳环中显影极性的取代基的稳定进行了讨论。