Steric Effects in Elimination Reactions. II. The Effect of the Steric Requirements of Alkyl Substituents upon the Extent and Direction of Unimolecular Elimination in the Solvolysis of Tertiary Alkyl Bromides
Steric Effects in Elimination Reactions. II. The Effect of the Steric Requirements of Alkyl Substituents upon the Extent and Direction of Unimolecular Elimination in the Solvolysis of Tertiary Alkyl Bromides
<i>Syn</i>-Selective Synthesis of β-Branched α-Amino Acids by Alkylation of Glycine-Derived Imines with Secondary Sulfonates
作者:Sha Lou、Grace M. McKenna、Steven A. Tymonko、Antonio Ramirez、Tamas Benkovics、David A. Conlon、Francisco González-Bobes
DOI:10.1021/acs.orglett.5b02448
日期:2015.10.16
syn-selective synthesis of β-branchedα-aminoacids has been developed based on the alkylation of glycine imine esters with secondary sulfonates. The potassium counterion for the enolate, the solvent, and the leaving group on the electrophile were key levers to maximize the diasteroselectivity of the alkylation. The optimized conditions enabled a straightforward preparation of a number of β-branched α-amino