Health & Environmental Research Online (HERO)


Print Feedback Export to File
7947243 
Journal Article 
BORANE REACTIONS .9. STEREOCHEMISTRY OF HYDROBORATION OF CYCLOHEX-2-ENONES, CYCLOHEX-2-ENOLS, CYCLOHEXAN-1,2 AND 1,3-DIONES 
Dunkelblum, E; Klein, J; Levene, R 
1972 
1 
Tetrahedron
ISSN: 0040-4020 
28 
4 
1009-+ 
English 
WOS:A1972L628700016 
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. 1972.