polythioether, and polysulfonamide products. These photocyclization reactions follow sequential single electron transfer (SET)-desilylation pathways. Only in the cases of phthalimides, bearing mixed ether-thioether N-substituents, do these excited-state cyclization reactions proceed with lower degrees of regioselectivity. This is a result of competitive desilylation and alpha-to-sulfur deprotonation reactions
辐照包含N-连接的ω-三甲基甲
硅烷基甲基取代的聚醚,聚
硫醚和聚磺酰胺链的邻苯二甲
酰亚胺可有效生产相应的大环聚醚,聚
硫醚和聚磺酰胺产品。这些光环化反应遵循顺序的单电子转移(
SET)-去甲
硅烷基化途径。仅在带有混合的醚-
硫醚N-取代基的邻苯二甲
酰亚胺的情况下,这些激发态环化反应才会以较低的区域选择性进行。这是由初始
SET形成的两性离子双自由基中间体发生竞争性甲
硅烷基化和α-
硫脱质子反应的结果。