Organotin chemistry. Part XI. The preparation of organotin alkoxides

Abstract

Trialkyltin alkoxides, R₃SnOR′, can be prepared conveniently by thermal decarboxylation of a mixture of the oxide, (R₃Sn)₂O, and dialkyl carbonate, (R′O)₂CO, or (except when R = Me or Et) by azeotropic dehydration of a mixture of the bistrialkyltin oxide and alcohol, R′OH. Under these latter conditions, dibutyltin oxide forms the 1,1,3,3-tetra-butyl-1,3-dialkoxydistannoxanes, (R′O)Bu₂Sn·O·SnBu₂(OR′), which (except when R = Me) decompose on distillation into the dialkoxide, Bu₂Sn(OR′)₂, and oxide, Bu₂SnO.

The temperature at which the n.m.r. coupling between tin atoms and the alkoxy-groups is broken in the alkoxides Bu₃SnOR′ shows that the rate of exchange follows the sequence MeO > EtO > PhCH₂·O > Me₃C·CH₂·O, Me₂CH·O, PhMeCH·O, Ph₂CH·O.