Abstract

Three chiral electron-deficient phosphine ligands, (4R,15R)-,3-bis(trifluoromethanesulfonyl)perhydro-1,3,2-benzodiazaphosphol-2-yldiethylamine, C12H20F6N3O4PS2, (IIIa), (4R,5R)-1,3-bis(trifluoromethanesulfonyl)perhydro-1,3,2-benzodiazaphosphol-2-yldimethylamine, C10H16F6N3O4PS2, (IIIb), and bis(4R,5R)-1,3-bis(trifluoromethanesulfonyl)perhydro-1,3,2-benzodiazaphosphol-2-ylmethylamine, (IV), as the chloroform solvate, C17H23F12N5O8P2S4.0.98CHCl3, have been prepared from (1R,2R)-N,N'-bis(trifluoromethanesulfonyl)-1,2-cyclohexanediamine and diethyl phosphoramidous dichloride, dimethyl phosphoramidous dichloride or methyl imidodiphosphorus tetrachloride. The -acceptor abilities of these new types of ligands have been evaluated by X-ray determination of the P-N bond lengths; it has been found that the most promising ligand is the bis(phosphine) (IV).