Reactions of 2-alkoxy-3-alkyl-1,3,2-oxazaphosphinanes with alkyl chloroformates

2-Alkoxy-3-alkyl-1,3,2-oxazaphosphinanes containing a sterically hindered N atom react with alkyl chloroformates according to the Arbuzov mechanism only. The ratio of the open and cyclic reaction products depends on the nature of the alkoxy group in the starting phosphinane. With a less hindered N atom, acylation at the N atom gives acyclic chloridophosphites, in addition to the Arbuzov-type products. The structures of the chloridophosphites were confirmed by their chemical transformations into stable thiophosphates. Oxazaphosphinane analogs of phosphorylformamides and phosphorylformohydrazide were obtained.