Md. Andrews et al., REGIOSELECTIVE DIECKMANN CYCLIZATIONS LEADING TO ENANTIOPURE HIGHLY FUNCTIONALIZED TETRAMIC ACID-DERIVATIVES, Journal of the Chemical Society. Perkin transactions. I, (2), 1998, pp. 223-235
Regioselective Dieckmann cyclisations using an N-acyloxazolidine deriv
ed from L-serine give substituted tetramic adds in high yield and enan
tioselectivity, The products are easily deprotected under mild conditi
ons to give hydroxymethyltetramic acids.