One-pot synthesis of cyclopropane derivatives with a cis : Trans stereoselectivity by Wittig olefination-sulfur ylide cyclopropanation sequence

摘要

Cyclopropane derivatives were synthesised in one pot from aromatic aldehydes, phenacyltriphenylphosphonium bromide, and S-phenacylthiolanium bromide by a Wittig olefination-sulfur ylide cyclopropanation sequence. When Cs2CO3 was used as the base and CH3CN/water (8:2, v/v) as the solvent, the major product was the cis-1,2-dibenzoyl cyclopropane. In contrast, when using DBU as the base and MeOH as the solvent, the major product was transdibenzoyl cyclopropane. In some cases, the major isomer was obtained in high purity and good yield by simple filtration.