Diastereoselective Addition of Prochiral Nucleophilic Alkenes to α-Chiral N-Sulfonyl Imines.

Abstract

The Lewis-acid-promoted addition of prochiral E- and Z-allyl nucleophiles to chiral α-alkoxy N-tosyl imines is described. Alkene geometry is selectively transferred to the newly formed carbon-carbon bond, resulting in stereochemical control of C1, C2, and C3 of the resulting 2-alkoxy-3-N-tosyl-4-alkyl-5-hexene products. A computational analysis to elucidate the high selectivity is also presented. This methodology was employed in the synthesis of two naturally occurring isomers of clausenamide.