Stereochemical control in the reduction of 2-chromanols.
[reaction: see text] Reduction of C5-substituted 2-hydroxychromans selectively provides 2,4-cis-chromans using large silane reductants and 2,4-trans-chromans using the smaller silane PhSiH(3). The stereochemical outcome has been rationalized on the basis of a Curtin-Hammett kinetic situation arising from hydride delivery to two different conformations of an intermediate oxocarbenium ion. This method provides a powerful way to control the relative stereochemistry of these substructures which are prevalent in bioactive natural products.
Li
Kelin
K
Department of Chemistry, 1251 Wescoe Hall Drive, 2010 Malott Hall, University of Kansas, Lawrence, Kansas 66045-7582, USA.
Vanka
Kumar
K
Thompson
Ward H
WH
Tunge
Jon A
JA
D001688:Biological Products / Q000737:chemistry*; D002384:Catalysis; D002839:Chromans / Q000138:chemical synthesis / Q000737:chemistry*; D002934:Cinnamates / Q000737:chemistry; D015394:Molecular Structure; D010084:Oxidation-Reduction; D010636:Phenols / Q000737:chemistry; D012821:Silanes / Q000737:chemistry; D013237:Stereoisomerism
D001688:Biological Products; D002839:Chromans; D002934:Cinnamates; D010636:Phenols; D012821:Silanes; C029010:cinnamic acid