STEREOSELECTIVE SYNTHESIS OF 2,3-EPOXY-AMIDES BY ALDOL-LIKE CONDENSATION OF 2,3-O-ISOPROPYLIDENE-D-GLYCERALDEHYDE WITH N,N-DIETHYL DIAZOACETAMIDE

The 1:1 mixture of cis:trans epoxy-amides 5c was obtained quantitatively by condensation of 2,3-O-isopropylidene-D-glyceraldehyde 1 with N,N-diethyl diazoacetamide. Similarly, the reaction of 1 with methyl diazopropionate was studied and gave as the main product the beta-ketoester 4b (product of a 1,2-hydrogen shift) and, in a low yield, the glycidic ester 5b (intramolecular nitrogen displacement). The configuration at C-3 of the resultant epoxides of both reactions revealed that the addition step was completely stereoselective. Under similar conditions, compound 6, methyl 3-hydroxy-2-diazopropionate was unreactive, but with heating gave 7.