Diastereoselective synthesis of a highly functionalized cyclohexene embedded with a quaternary stereogenic centre by self Diels-Alder dimerization of a [3]dendralene attached to a (-)-menthol auxiliary

摘要

A novel route to a chiral functionalized [3]dendralene attached to a (-)-menthol auxiliary has been developed, which involves a dimethylsulfonium methylide mediated olefination of a substituted ethenylidene phosphonoacetate (-)-menthyl ester, followed by a Horner-Wordsworth-Emmons reaction with 4-bromobenzaldehyde. The chiral [3]dendralene was reactive enough to undergo intermolecular Diels- Alder cyclodimerization to give the highly substituted cyclohexene with very high regio- and diastereoselectivity.