ASYMMETRIC SYNTHESES AND LANTHANIDE-INDUCED CD STUDIES OF (24R AND 24S) 5-BETA-CHOLESTANE-3-ALPHA, 7-ALPHA, 12-ALPHA, 24, 25-PENTOLS

Authors
DAYAL B RAO K SALEN G SEONG WM PRAMANIK BN HUANG EC TOOME V
Citation
B. Dayal et al., ASYMMETRIC SYNTHESES AND LANTHANIDE-INDUCED CD STUDIES OF (24R AND 24S) 5-BETA-CHOLESTANE-3-ALPHA, 7-ALPHA, 12-ALPHA, 24, 25-PENTOLS, Pure and applied chemistry, 66(10-11), 1994, pp. 2037-2040
Citations number
19
Categorie Soggetti
Chemistry
Journal title
Pure and applied chemistry → ACNP
ISSN journal
00334545
Volume
66
Issue
10-11
Year of publication
1994
Pages
2037 - 2040
Database
ISI
SICI code
0033-4545(1994)66:10-11<2037:ASALCS>2.0.ZU;2-R
Abstract
5beta-cholest-24-ene-3alpha,7alpha,12alpha-triol was efficiently conve rted to the corresponding (24R and 24S) isomers of eta-cholestane-3alp ha,7alpha,12alpha,24,25-pentols with the Os-catalyzed Sharpless asymme tric dihydroxylation process. Utilizing a new phthalazine class of cin chona alkaloid based ligands, namely (DHQD)2PHAL and (DHQ)2PHAL and th e use of methylsulfonamide for the acceleration of the reaction rate, the enantiomeric excess achieved ranged from 95-98%. The absolute conf igurations and enantiomeric excess of the eta-cholestane-3alpha,7alpha ,12alpha,24,25-pentols achieved were confirmed by the lanthanide-induc ed CD Cotton effect Measurements.