SUBSTITUENT EFFECTS FOR THE BF_3-MEDIATED REACTIONS OF ALLYLTRIBUTYLTIN AND ALLYLTRIETHYLLEAD WITH BENZALDEHYDE

摘要

Substituent effects were measured for the reactions of substituted benzaldehydes with allyltributyltin (1) and allyltriethyllead (2) reagents in the presence of BF_3·OEt_2 in CH_2Cl_2. The Hammett ρ values were small and positive at 25℃ and negative at -78℃ for both 1 and 2. These could be interpreted in terms of the contribution of electrophilic complexation between the aldehyde function and BF_3 as a rate-limiting step. A large negative ρ value was observed for the complex-formation equilibria between substituted benzaldehydes and BF_3.