Optically Active 6-Membered P-Heterocycles: 1-Phenyl-1,2-Dihydrophosphinine Oxide and 1-Phenyl-3-Diphenylphosphinoyl-1,2,3,6-Tetrahydrophosphinine Oxide

The antipodes of racemic 1-phenyl-1,2-dihydrophosphinine oxides 1A and 1B were separated by resolution via formation of a diastereomeric complex using (-)-(2R,3R)-α,α,α',α'-tetraphenyl-1,4-dioxaspiro[4.5]decan-2,3-dimethanol (spiro-TADDOL) 2. The (+)-antipode of 1-phenyl-3-diphenylphosphinoyl-1,2,3,6-tetrahydrophosphinine oxide 3 was synthesized by the diastereoselective addition of diphenylphosphine oxide to the α,β-double-bond of (-)-1,2- dihydrophosphinine oxide 1A. The new chiral tetrahydrophosphinine oxide (+)-3 served, after double deoxygenation, as a novel P-chiral bidentate ligand in the corresponding platinum complex.