The synthesis of E enol ethers of protected 4-amino aldehydes

Abstract

The title compounds, a novel class of protected homoallylic amines, have been synthesised by a short and efficient route. Acrolein acetals were converted by a modified Michaelis–Arbuzov reaction into α-alkoxyallyl(diphenyl)phosphine oxides. 1, 3-Dipolar cycloaddition to the alkene part of these molecules gave 5-diphenylphosphinoyl-4,5-dihydroisoxazoles, which were reductively cleaved to obtain δ-amino-β-hydroxy-α-alkoxyalkyl(diphenyl)phosphine oxides. After selective protection as the N-acetyl derivatives, stereospecific Wittig–Horner diphenylphosphinic acid elimination gave the title compounds.