- Lithium Aluminium Hydride Reduction of Pregnenolone under Conditions of Assumed Kinetic and Equilibrium Control
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Reduction of pregnenolone (1) with lithium aluminium hydride (LAH) yields pregn-5-ene-3β,20α-diol (2a) and its 20β epimer (2b) in a ratio of 1:3.8.Reduction with LAH/AlCl3 under equilibrating conditions, using an excess of 1, gave a complex product mixture containing 2a and 2b in a ratio of 1:9, pregna-3,5-dien-20-one (3), pregna-3,5-dien-20-ols (4a and 4b), pregn-4-ene-20α-ol-3-one (6a), its 20β epimer (6b) as well as small amounts of other compounds, probably pregn-4-ene-3,20-diols.A reaction scheme is presented which accounts for the formation of the various reaction products.
- Allenmark, Stig,Boren, Hans
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p. 407 - 410
(2007/10/02)
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