Asymmetric sharpless epoxidation of divinylcarbinol. Erythro-D- and -L-4-pentenitols by hydrolysis of regioisomeric epoxy-4-pentenols

The asymmetric Sharpless epoxidation of divinylcarbinol (1), a secondary, achiral allylic alcohol, is described in detail. The epoxidation proceeds with high enantio-control and diastereo-selection. The resulting 1,2-epoxy-4-pentene-3-ols 2 are equilibrated to afford the internal epoxides 5. Hydrolysis of the regioisomers 2 and 5, respectively, furnishes opposite enantiomers of erythro-4-pentenitols 3 with high selectivity. Several derivatives of 3 are described, as well as results of a less stereoselective route - from D-glyceraldehyde acetonide (10) - providing NMR data of the threo series. -The acute toxicity of divinylcarbinol (1) is reported, along with the mutagenicity of 1, L-2 and L-5 as determined by Ames tests.