Synthesis of Vinylogous β-Amino Esters from N-(N,N-Dialkylaminoalkyl)benzotriazoles

Abstract

Treatment of N-(N,N-dialkylaminoalkyl)benzotriazoles with 4-bromocrotonates in the presence of zinc provides a new route to 5-(N,N-dialkylamino)-2-alkenoate esters. This is formally the result of the γ-addition of zinc dienolate reagents to iminium cations formed in situ by dissociation of the aminoalkylbenzotriazoles. When N-allyl protecting groups are incorporated into the benzotriazole substrate, deallylation of the tertiary allylamine products gives also a ready access to the corresponding secondary amines.

Acknowledgments

Financial support was provided by Universidad del País Vasco (UPV 170.310-EC201/94), Ministerio de Ciencia y Tecnología (DGI BQU2000-01354), and Janssen-Cilag. A fellowship to A.F. (Gobierno Vasco) is also gratefully acknowledged.