A Chiral N-Sulfonylphosphoramide: Synthesis and X-ray Crystal Structure of a 1,3,2-Oxazaphospholidin-5-one, a Trivalent Electron-Withdrawing Amino Acid-Derived Phosphorus Compound, and Synthesis of Its W(CO)(5) Adduct.

Abstract

Reaction of the amino acid derivative (S)-N-tolylsulfonylvaline with PhPCl2 and NEt3 gives in >90% yield a novel chiral phosphorus heterocycle as a greater than 7:1 mixture of diastereomers. The X-ray crystal structure of the major isomer 7a shows that the isopropyl and phenyl groups are mutually cis. The IR spectrum of the W(CO)5 adduct of 7a shows that the N-sulfonyl and carboxylate moieties make it a strongly electron-withdrawing ligand.