Stereoselective synthesis of β-substituted aspartic acids via tetrahydro-1,3-oxazin-6-ones
摘要:
Oxazinones have been synthesised and used as chiral templates in the synthesis of beta-substituted aspartic acids. Use of a Brebereck's reagant/Grignard/hydrogenation strategy gave cis-oxazinones with complete stereoselectivity, whereas an alkylation strategy, although trans-selective, gave mixtures of isomers. The oxazinones could be convened to beta-substituted aspartic acids and to regioselectively protected beta-substituted aspartic acids without loss of stereochemistry at either centre. (C) 1999 Elsevier Science Ltd. All rights reserved.