S. E. Ealick

CARBON-13 NMR STUDIES OF 1-PHENYL-4-PHOSPHORINANONE AND DERIVATIVES. SINGLE CRYSTAL X-RAY DIFFRACTION ANALYSIS OF 1-PHENYL-4-PHOSPHORINANONE 1-OXIDE AND 1-SULFIDE

Abstract The 13C nmr spectral analysis has been recorded for the title compounds in DCC13, and all data appear to be in a accord with chair forms. Single crystal x-ray diffraction analysis of 1-phenyl-4-phosphorinanone 1-oxide and the corresponding sulfide revealed flattened chair forms in the solid state. Neither the solution data nor the x-ray data provided any evidence for a twist form for either compound as has been suggested for the carbon counterpart, namely, cyclohexane-1,4-dione.

CARBON-PHOSPHORUS HETEROCYCLES. SYNTHESIS OF SUBSTITUTED 2,3,4,5-TETRAHYDRO-5-OXO-2,2-DIPHENYL-1H-2-BENZOPHOSPHEPINIUM SALTS VIA INTRAMOLECULAR ACYLATION WITH 115% POLYPHOSPHORIC ACID

Abstract Intramolecular acylation involving three ω-carboxyalkylphosphonium salts 1a-c has been achieved in the presence of 115% polyphosphoric acid (PPA) to yield the heretofore unknown 2,3,4,5-tetrahydro-5-oxo-2,2-diphenyl-1H-2-benzo-phosphepinium salts 2a-c. The open-chain precursors were easily prepared by quaternization of the corresponding tertiary arylmethyl-substituted phosphines with 3-chloropropanoic acid. Cyclization of the carboxy-substituted salts was accomplished at 200°C with PPA in modest yields (37–64%). A mechanism reminiscent of a classic electrophilic acylation process was tentatively proposed. An x-ray crystallographic analysis of a single crystal of 2a showed the phosphepin ring to exist in a twisted-chair conformation.