acetaldehyde enolate; sulfuric acid in tetrahydrofuran 1) reflux, 1 h, 2) r.t., 10 min.; also with K2CO3 or MeO- as base;

Lithium enolate of the acetaldehyde; ammonium chloride in tetrahydrofuran 1) reflux, 1 h, 2) r.t., 10 min.; also with K2CO3 or MeO- as base; other 5-hydroxyisooxazolidines; Product distributionMechanism;