N-(ω-三甲基硅烷基醚)马来酰亚胺的光诱导单电子转移反应

Photoinduced Single Electron Transfer Reactions of N-(ω-Trimethylsilylether)maleimides

合成了两个N-(ω-三甲基硅烷基醚)马来酰亚胺衍生物(2a,2b),并以2a,2b为光反应底物在HCN,MeOH,30%H_2O-HCN,丙酮等溶剂中进行了光反应.结果显示,化合物2a在强的亲硅性溶剂MeOH,30%H_2O-MeOH,30%H_2O-HCN中经单电子转移反应以很高的产率和区域选择性生成环胺醇产物3,在HCN、丙酮等弱的亲硅性溶剂中发生[2+2]环加成副反应生成双分子偶合产物5;2b无论是在强的亲硅性溶剂,还是在弱的亲硅性溶剂HCN、丙酮中,部发生分子内单电子转移反应,生成分子内双离子自由基中间体8.一部分8发生脱三甲基硅烷基反应生成环化物4的前体分子内双自由基9,多数8发生特殊的分子间偶合反应得到不对称双分子偶合产物6.所有新化合物均经NMR和质谱验证.

Two N-（ω-trimethylsilylether）maleimides （2a, 2b） were synthesized and their photoreaction procedures in different solvents, such as HCN, MeOH, 30% H2O-MeOH, 30% H2O-HCN and acetone, were investigated respectively. The results showed that, 2a occurred intramolecular single electron transfer （SET） to provide cyclic amidol 3 with highly yield and highly regioselectivity in silophiles such as MeOH, 30% H2O-MeOH, 30% H2O-MeCN, and occurred side reaction to produce [2＋2] dimerization product 5 in the weak silophiles HCN and acetone. 2b occurred intramolecular SET to provide intermediate zwitterionic radicals 8 in all the highly and weak silophiles. A few of 8 occurred desilylation to produce intramolecular biradicals 9 which is the precursor of the cyclic amidol 4. Most of 8 occurred intermolecular radicals coupling to produce cyclic asymmetric dimerization compound 6. Structures of all compounds were characterized by MS （EI）, NMR data.