Silica-Gel-Catalysed Knoevenagel Condensation of Peptidyl Cyanomethyl Ketones with Aromatic Aldehydes and Ketones. A Novel Michael Acceptor Functionality for C-Modified Peptides: The Benzylidene and Alkylidene Cyanomethyl Ketone Function

Article abstract of DOI:10.1021/jo00032a042

Simple preparation of cyanomethyl ketone derivatives 5a-5b of N-acetylphenylalanine and N-acetylleucylphenylalanine is accomplished by condensation of the corresponding activated carboxylic acids 3a-3b and the carbanion of tert-butyl cyanoacetate to give