Asymmetric Michael addition of a glycine synthon to methyl methacrylate, mediated by disodium TADDOLate

The disodium salt of (4R,5R)-(TADDOL), 3, can be used as a mediator in the asymmetric Michael reaction, e.g. 1,4-addition of a glycine synthon 1 to methyl methacrylate 2, mediated by 3 (10–100 mol%), gives a diastereoisomeric excess of the corresponding product 4 up to 65% and an enantiomeric purity ca. 28%; (2S,4R)-4-methylglutamic acid (ee ≥ 85%), 6, was obtained starting from (2S,4R)-4 (ee 28%) through the recrystallization and decomposition of the latter.