Reaction of 2-acetyl-5-methyl-2H-1,2,3-diazaphosphole with butane-2,3-diol

The reaction of 2-acetyl-5-methyl-2H-1,2,3-diazaphosphole with (rac)-butane-2,3-diol at temperatures below 0 °C leads to the formation of a hydrospirophosphorane containing both a diazaphospholene and a dioxaphospholane ring system and a β-hydroxyalkoxy-1,2,3-diazaphospholene. On heating, these products form a hydrospirotetraoxaphosphorane, its tautomeric monocyclic β-hydroxyalkylphosphite and N-acetyl-N’-isopropylidene-hydrazine.