Efficient synthesis of optically active α-quaternary amino acids by highly diastereoselective [2,3]-rearrangement of allylic ammonium ylides
作者:Ting-Shun Zhu、Ming-Hua Xu
DOI:10.1039/c2cc33027j
日期:——
A pincer-like chiral auxiliary strategy for synthesizing various optically active α,α-disubstituted amino acids in high yields with excellent enantioselectivities is described.
Catalytic α-Allylation of Unprotected Amino Acid Esters
作者:Ping Fang、Mani Raj Chaulagain、Zachary D. Aron
DOI:10.1021/ol300665n
日期:2012.4.20
Catalytic alpha-allylation of unprotected amino acid esters to produce alpha-quaternary alpha-allyl amino acid esters is reported. Catalytic loadings of picolinaldehyde and Ni(II) salts induce preferential reactivity at the enolizable alpha-carbon of amino acid esters over the free nitrogen with electrophilic palladium pi-allyl complexes. Fourteen examples are given. Additionally, the use of chiral ligands to access enantioenriched alpha-quaternary amino acid esters from racemic precursors is demonstrated by the enantioselective synthesis of alpha-allyl phenylalanine methyl ester from racemic phenylalanine methyl ester.