ChemInform Abstract: 2-Alkyl-5,5-dimethyl-1,3,2-dioxaphosphorinan-2-ones α-Lithiated Carbanions. Synthesis, Stability, and Conformation.

ChemInform Abstract

The formation of the desired compound by the action of an alkyl lithium reagent upon the parent phosphate cannot be performed owing to a higher electrophilicity of the phosphorus center. However, the metalation of the cyclic phosphonates (VI) ((VIa): space group P2₁2₁2₁, Z = 8) yields the derivatives (VIII) and (IX), two rapidly interconverting species. They are thermally unstable, but can be stabilized by the presence of one equiv. of LiBr or of LDA. A ³¹P NMR study of the self condensation of these species shows that the P atom in the axial conformation (IX) is more electrophilic than in the equatorial one (VIII).