Enantioselective intramolecular cyclopropanation of N-allylic- and N-homoallylic diazoacetamides catalyzed by chiral dirhodium(II) catalysts
摘要:
Diazodecomposition of N-(tert-butyl)-N-(3-buten-1-yl)diazoacetamides catalyzed by dirhodium(II) tetrakis[methyl 2-pyrrolidone-5(S)-carboxylate], Rh-2(5S-MEPY)(4), and tetrakis[methyl 2-oxazolidinone-4(S)-carboxylate], Rh-2(4S-MEOX)(4), forms products from intramolecular cyclopropanation in good yields with enantiomeric excesses ranging from 60-90%. Intramolecular cyclopropanation with N,N-diallyldiazoacetamide (72% ee) is competitive with intramolecular [3+2] dipolar cycloaddition.