Asymmetric Synthesis of β-Amino Acids. 1. Highly Diastereoselctive Addition of a Racemic β-Alanine Enolate Derivative to Electrophiles

Article abstract of DOI:10.1021/jo00007a053

β-Alanine, an inexpensive β-amino acid, was converted into the 2-tert-butylperhydropyrimidin-4-one derivative 2, which can be alkylated with high stereoselectivity via the corresponding enolate.The high diastereoselectivity observed for the reaction of 2-Li with electrophiles seems to be due to steric hindrance generated by an axial disposition of the tert-butyl group at C(2), which directs addition from the enolate face opposite to this group.The hydrolysis of the resulting adducts proceeds with 6N hydrochloric acid to affford α-substituted β-amino acids in good yields.These results pave the road to the development of a new asymmetric synthesis of enantiomerically pure α-substituted β-amino acids.