The regioselective 1,4-addition reaction of alkenylboronic acids to α,β,α′,β′-unsaturated ketones

Article abstract of DOI:10.1246/bcsj.71.2403

The effect of substituents on the double bond of α,β-unsaturated ketones for the 1,4-addition reaction rate of alkenylboronic acids induced by cyanuric fluoride was studied in detail. When the steric hindrance around the β-carbon of the unsaturated ketones increased, the 1,4-addition reaction rate significantly decreased. An alkyl substituent on the α-carbon was also found to significantly affect the 1,4-addition reaction. From these results, unsymmetric α,β,α′,β′unsaturated ketones (10a-f) were designed for the regioselective 1,4-addition reaction with alkenylboronic acids (4a-j). Since they have substituents to disturb the 1,4-addition reaction on only one double bond, the alkenylboronic acids reacted with them from only one side to selectively provide γ,δ,α′,β′-unsaturated ketones (11a-q). Further transformations of the resulting γ,δ,α′,β′-unsaturated ketones were also performed.