Synthesis of (3R,6R)- and (3S,6S)-3,6-dialkylpiperazin-2,5-dione derivatives as useful intermediates to both (R) and (S) α-aminoacids

Article abstract of DOI:10.1016/S0957-4166(00)86217-5

The alkylation of 2 leads to a diastereomeric mixture where 4 is generally present in greater amounts than 3. The successive alkylation of 4 affords exclusively the cis derivatve, 7, while a cis/trans mixture is obtained from isomer 3. In alkaline solutio