Irradiation (λ > 340 nm) of the title compound 2a in t-BuOH affords 3,3,10,10-tetramethyl-2,8-dioxatricyclo-[4.3.2.01,6]undecane-5,9-dione (3)via photoextrusion of 2-methylpropene and subsequent photocycloaddition of 2a to the alkene. The same regioisomer 3 is formed selectively and in much higher yields on irradiating 2a in the presence of excess 2-methylpropene. Irradiation of 3 (λ = 300 nm) in t-BuOH
在t -BuOH中辐照(λ> 340 nm)标题化合物2a,得到3,3,10,10-四甲基-2,8-二氧杂
三环-[4.3.2.0 1,6 ]
十一烷-5,9-二酮(3 )通过
2-甲基丙烯的光挤出和随后2a的光环加成到烯烃中。在过量的
2-甲基丙烯的存在下,在辐射2a下选择性地并且以高得多的产率形成相同的区域异构体3。在相同的烯烃存在下,在
叔丁醇中辐照3(λ= 300 nm),得到螺环氧杂
环丁烷7a和7b的6:1混合物,但没有α裂解产物。在2-
丙醇中2a被光还原为非对映异构体二聚体9的2:1混合物。