E. Dunkelblum, R. Levene, J. Klein
1972
Citations
0
Influential Citations
20
Citations
Journal
Tetrahedron
Abstract
Abstract The hydroboration of a number of substituted α,β-unsaturated cyclohexenones and cyclohexenols has been studied. The ketones and the pseudo equatorial alcohols yielded the diequatorial trans -1,2-diols in fair yields, accompanied by minor amounts of 1,3-diols. The directive effect of the intermediate allylic borate and the steric influence of ring substituents on this reaction has been established. The hydroboration of 1,3-cyclohexandiones has been shown to proceed mainly by an addition elimination process yielding diequatorial trans -1,2-cyclohexandiols, thus transforming a 1,3-dioxocyclohexane to a 1,2-dioxocyclohexane, 1,2-Cyclohexandione gave, on hydroboration, mainly cis -1,2-cyclohexandiol. Mechanisms for the hydroboration of 1,2 and 1,3-cyclohexandiones are proposed, both involving, to some extent, an unusual intramolecular displacement of borate or borane by hydrogen with retention of configuration.