Synthesis of novel amino squaric acids via addition of dianion enolates derived from N-Boc amino acid esters

Novel α-amino squaric acid analogs were synthesized by initial addition reaction of a dianion enolate generated from N-Boc amino acid tert-butyl ester to squaric acid diisopropyl ester, and subsequent decarboxylation of the resulting carboxylic acid moiety.