Intramolecular vs. intermolecular induction in the diastereoselective catalytic reduction of enantiomerically pure ketones with borane in the presence of cyclic β-amino alcohols
✍ Scribed by I. Reiners; J. Wilken; J. Martens
- Book ID
- 103977331
- Publisher
- Elsevier Science
- Year
- 1995
- Tongue
- English
- Weight
- 433 KB
- Volume
- 6
- Category
- Article
- ISSN
- 0957-4166
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✦ Synopsis
Asymmetric reduction of various enantiomerically pure ketones was carded out by using oxazaborolidine catalysts with a variety of achiral and chiral ligands. The efficiency of chiral 1,2-amino alcohols as well as the effect of the stereogenic centers in the substrate on the catalytic asymmetric reduction were studied. It was found that the corresponding secondary alcohols were obtained with extremely high stereoselectivities with the proper choice of chiral ligands although a considerably large double asymmetric induction was observed in some cases.
📜 SIMILAR VOLUMES
## 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 excl