Stereoselectivity in deoxygenation of 5-hydroxy-5-phosphinyl-hexofuranoses (alpha-hydroxyphosphonates).

The addition of dimethyl phosphonate to six different hexofuranos-5-uloses in the presence of DBU, followed by esterification with methoxalyl chloride and then radical reduction, afforded 5-deoxy-5-dimethoxyphosphinyl-D- and L-hexofuranoses. The stereoselectivity of the deoxygenation and possible transition-state models are discussed.