title: Bifunctional Brønsted Base Catalyzes Direct Asymmetric Aldol Reaction of α-Keto Amides.
abstract: The first enantioselective direct cross-aldol reaction of α-keto amides with aldehydes, mediated by a bifunctional ureidopeptide-based Brønsted base catalyst, is described. The appropriate combination of a tertiary amine base and an aminal, and urea hydrogen-bond donor groups in the catalyst structure promoted the exclusive generation of the α-keto amide enolate which reacted with either non-enolizable or enolizable aldehydes to produce highly enantioenriched polyoxygenated aldol adducts without side-products resulting from dehydration, α-keto amide self-condensation, aldehyde enolization, and isotetronic acid formation.
authors.affiliation: Departamento de Química Orgánica I, Facultad de Químicas, Universidad del País Vasco, Apdo. 1072, 20080, San Sebastián, Spain.
authors.forename: Haizea
authors.initials: H
authors.lastname: Echave
authors.affiliation: Departamento de Química Orgánica I, Facultad de Químicas, Universidad del País Vasco, Apdo. 1072, 20080, San Sebastián, Spain.
authors.forename: Rosa
authors.initials: R
authors.lastname: López
authors.affiliation: Departamento de Química Orgánica I, Facultad de Químicas, Universidad del País Vasco, Apdo. 1072, 20080, San Sebastián, Spain. claudio.palomo@ehu.es.
authors.forename: Claudio
authors.initials: C
authors.lastname: Palomo
keywords: Brønsted bases; aldol reaction; asymmetric catalysis; organocatalysis; synthetic methods