摘要:
A synthesis of L-proline where all of the ring methylenes me stereoselectiveiy labelled with deuterium is described. A catalytic deuteration of protected 3,4-dehydro-L-proline using transition metal catalyst followed by RuO4-oxidation gave a [3,4-D-2]pyroglutamic acid derivative. A syn-selective deuteration of the aminal derived from the pyroglutamate with Et3SiD-BF3. OEt2 furnished (2S,3S,4R,5S)-[3,4,5-D-3]proline. The present procedure is also applied to the synthesis of the corresponding (2S,3S,4R,SR)-isomer. (C) 1999 Elsevier Science Ltd. All rights reserved.