Diastereoselectivity and Reaction Pathway of the Reactions of Benzaldehyde with Allylic Iodides in the Presence of Sn or Pb

Article abstract of DOI:10.1246/bcsj.65.2145

The relative reactivity and stereoselectivity were determined in the Sn- Pb-promoted reactions of substituted benzaldehydes with 3-iodo-1-propene and 1-iodo-2-butene.The reactivity data suggested that the reactions go through a direct nucleophilic addition mechanism.No indication of the occurrence of electron transfer was obtained by the dehalogenation probe experiment.The diastereoselectivity was low in the Sn/THF system but was high in Pb/DMF.Large solvent effects were observed in the erythro selectivity for the Sn-promoted reaction; erythro:threo ratio was 31:69 in CH2Cl2 and 84:16 in HMPA.