Chemoselective N-Ethylation of Boc Amino Acids without Racemization

Article abstract of DOI:10.1021/jo00207a007

The Boc derivatives of amino acids such as phenylalanine, methionine, and tyrosine benzyl ethers have been selectively ethylated to give, respectively, the enantiomerically pure Boc-N-ethyl amino acids 12, 20, and 23.The benzyl, trimethylsilyl, and tert-b