Jang B. Rampal

CARBON-PHOSPHORUS HETEROCYCLES. REACTIONS OF THE ENAMINE 1-(1,2,3,6-TETRAHYDRO-1-PHENYL-4-PHOSPHORINYL) PYRROLIDINE P-SULFIDE WITH ACTIVATED ALKENES AND ACID ANHYDRIDES

Abstract The enamine of 1-phenyl-4-phosphorinanone 1-sulfide has been prepared for the first time from the ketone and pyrrolidine in benzene. Crude enamine could be cyanoethylated at carbon. Hydrolysis of the product followed by treatment of the nitrile with aqueous KOH gave the corresponding carboxylic acid. Reduction of this keto acid with NaBH4 in alkaline medium gave the expected carbinol which lactonized spontaneously. Independent synthesis of the keto acid was achieved by adding methyl acrylate to the crude enamine followed by hydrolysis. The crude enamine also reacted with methyl vinyl ketone in dry benzene. Surprisingly, the product was a bicyclic unsaturated ketone which apparently formed via an aldol type condensation (intramolecular) during the hydrolysis of the enamine reaction mixture (hydrolysis was effected with H2O/CH3CO2H/NaO2CCH3). Interestingly, the crude enamine did not react with mesityl oxide or 1-acetyl-1-cyclohexene as only starting material and a polymeric substance could be obtai...