Comparison of photomacrocyclization reactions of trimethylsilyl- and tributylstannyl-terminated phthalimido- and maleimido-polyethers

SET-promoted photomacrocyclization reactions of trimethylsilyl- and tributylstannyl-terminated phthalimido- and maleimido-polyethers were investigated. The results indicate that the excited state cyclization processes, which take place via sequential SET-destannation pathways, produce macrocyclic polyethers more efficiently than those involving sequential SET-desilylation routes do. In addition, differences in product distributions obtained from photoreactions of trimethylsilyl- and tributylstannyl-terminated maleimido-polylethers suggest that more than one mechanistic pathway is followed in excited-state reactions of the tin-containing substrates.