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 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. Structure of all compounds were characterized by MS (EI), NMR data.

Key words: >maleimide, photoreaction, single electron transfer, H-atom abstraction, dimerization