title: Expedient asymmetric synthesis of all four isomers of N,N'-protected 2,3-diaminobutanoic acid.
abstract: 2,3-Diaminobutanoic acid (DAB) is found in several peptide antibiotics, toxins, and biologically active molecules. This paper describes the practical and highly enantioselective synthesis of all four N,N'-protected DAB stereoisomers using an asymmetric Rh(I)-phosphine-catalyzed hydrogenation of isomeric enamides as the key step. Thermal and photochemical isomerization of the enamide hydrogenation substrates coupled with catalyst-geometric isomer pairing allows targeted synthesis of single DAB isomers in maximum yield.
authors.affiliation: DuPont Pharmaceuticals Company, Chemical Process R&D, Experimental Station, Wilmington, Delaware 19880-0336, USA. A.Robinson@sci.monash.edu.au
authors.forename: A J
authors.initials: AJ
authors.lastname: Robinson
authors.forename: P
authors.initials: P
authors.lastname: Stanislawski
authors.forename: D
authors.initials: D
authors.lastname: Mulholland
authors.forename: L
authors.initials: L
authors.lastname: He
authors.forename: H Y
authors.initials: HY
authors.lastname: Li