A practical new chiral controller for asymmetric Diels-Alder and alkylation reactions

[GRAPHICS] 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.