The Reactions of (1-Halo-1-alkenyl)dialkylboranes with Lead(IV) Acetate or (Diacetoxyiodo)benzene. A Stereoselective Synthesis of 1-Halo-1,2-dialkylethylenes

Article abstract of DOI:10.1246/bcsj.53.1652

The reaction of (1-halo-1-alkenyl)dialkylboranes with lead(IV) acetate or (diacetoxyiodo)benzene was studied. (1-Bromo-1-alkenyl)dialkylboranes gave 1-bromo-1,2-dialkylethylenes.When alkyl groups on the boron atom of vinylboranes were bulky or the reaction temperatures were low, Z-isomers were afforded, whereas when alkyl groups on the boron atom were small or the reaction temperatures were relatively high, E-isomers were afforded as the main products. (1-Chloro-1-alkenyl)dialkylboranes gave (Z)-1-chloro-1,2-dialkylethylenes regardless of the reaction conditions. (1-Iodo-1-alkenyl)dialkylboranes failed to give satisfactory yields of 1-iodo-1,2-dialkylethylenes.