A practical new chiral controller for asymmetric Diels-Alder and alkylation reactions.
[formula: see text] The enantiomerically pure hydroxy sulfones (+)- and (-)-2 have been prepared from 1,2-epoxycyclohexane by a simple and practical procedure. The acrylate esters of these alcohols undergo BCl3-catalyzed Diels-Alder reactions with a variety of dienes at -78 to -55 degrees C in CH2Cl2 or C7H8 with high dienophile face selectivity (Table 1). The chiral esters so formed are readily cleaved with recovery of the controllers (+)- or (-)-2. Esters of (+)- and (-)-2 can be converted to Z-potassium enolates and alkylated with high face selectivity.
Sarakinos
G
G
Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, USA.
Corey
E J
EJ
D000478:Alkylation; D018360:Crystallography, X-Ray; D003500:Cyclization; D013237:Stereoisomerism; D013450:Sulfones / Q000138:chemical synthesis*
D013450:Sulfones