Triphenylethanediol-Derived 2-Chloro-1,3,2- dioxaphospholane: Synthesis,Structure, and Reaction with Chiral Alcohols

The reaction of (S)-1,1,2-triphenylethanediol (3) with phosphorus trichloride leads to the diastereoselective formation of (S _C,R _P)-2-chloro-1,3,2-dioxaphospholane (2). Its configuration has been determined by single crystal X-ray diffraction. When reacted with racemic secondary alcohols, diastereomeric phosphites are obtained, which display substantial shift differences in the ³¹P NMR spectra. Thus, chlorodioxaphospholane 2 can serve as derivatizing reagent for chiral secondary alcohols permitting to determine their enantiomeric excess.