MECHANISTIC STUDIES ON DECOMPOSITION OF TRIALKYLSTANNYLLITHIUMS

Article abstract of DOI:10.1016/S0022-328X(00)85569-2

The fast decomposition of trialkylstannyllithiums, R3SnLi (R=Me, Et and Bu), in the presence of hexaalkyldistannanes, R3SnSnR3, was observed, and its mechanism was investigated kinetically.Partial dissociation of R3SnLi into a complex in a solvent cage is suggested to occur in the initial step.The RLi in the complex can be trapped instantaneously by R3SnSnR3 to afford R4Sn and R3SnLi, and the counterpart R2Sn: by R3SnLi giving R3SnR2SnLi.The decomposition of R3SnLi followed first-order kinetics within 3.5 h, corresponding well to the rate of disappearance of R3SnSnR3 and of appearance of R4Sn.The partial dissociation rate constant (k₁) of Me3SnLi into the complex was determined as 2.0*10^-3 min^-1.The values of k₁ are about 100 times those of rate constants (k') for decomposition of R3SnLi in the absence of R3SnSnR3.Reformation of R3SnLi from the complex is highly significant.