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Borane Reduction of the Steroid 20-Ketone Group in the Presence of Various Chiral β-Amino Alcohols

✍ Scribed by Göndös, György ;Orr, James C.

Publisher
John Wiley and Sons
Year
1993
Tongue
English
Weight
173 KB
Volume
1993
Category
Article
ISSN
0947-3440

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✦ Synopsis

Abstract

The direction of reduction of 20‐carbonyl group of 3α‐hydroxy‐5β‐pregnan‐20‐one (1) with a complex of borane‐methyl sulfide and chiral β‐amino alcohols, depends on the chirality of the amino alcohol. Where there is a 2‐phenyl or 2‐benzyl substituent, then the S enantiomer gives exclusively the steroid 20__R__ alcohol 3. The R enantiomer of 2‐amino‐2‐phenyl‐1‐ethanol gives the highest steroid 20__S__ (2):20__R__ (3) alcohol ratio.

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