Syntheses, Structures, and Thermolyses of Three- and Four-Membered Heterocyclic Compounds Containing Highly Coordinate Main Group Elements

Most titled compounds were synthesized by taking advantage of the Martin ligand. Their structures were determined by X-ray crystallography. Thermolyses of most of the four-membered ring compounds gave the corresponding Wittig-type products, while those of 1,2-oxasiletanides in the presence of proton source afforded the homo-Brook rearrangement products depending on bulkiness of the substituent at the 3-position. Pentacoordinate thiasiliranides were hydrolyzed to give the corresponding thiol, which seems to be formed via the initial cleavage of the Si-C bond followed by further hydrolysis of the corresponding thia-Brook rearrangement product. On the other hand, the most polarized bond of a pentacoordinate selenaphosphirane was found to be the P-Se bond, which was confirmed by its reaction with CF3SO3Me to give the corresponding 1-(methylseleno)alkylphosphonium triflate and by the solvent-dependent NMR study.