Rhodium(II) catalyzed multi-component reactions of aryldiazoacetates with titanium(IV) isopropoxide and imines

Rh2(OAc)4 catalyzed diazo decomposition of aryldiazoacetates in the presence of titanium(IV) isopropoxide generated oxonium ylide intermediates. Trapping of the oxonium ylide intermediates with imines occurred subsequently via a nucleophilic addition. The three-component reaction of aryldiazoacetates, titanium(IV) isopropoxide, and imines gave α-alkoxyl-β-amino acid derivatives with C-N/C-C bond formation in a single step. Extension of the study to a four-component reaction with in situ generated imine was also investigated.