A series of substituted 1, 2, 6-triphenyl-4-phosphorinanones has been prepared, and a conformational analysis was performed on these systems. Condensation of phenylphosphine or bis (hydroxymethy1) phenylphwphine with appropriately substituted 1, 4-pentadien-3-ones gave the final products. For example, l-phenyl-2, 2, 6, 6-tetramethyl-4- phosphorinone was obtained which could be oxidized, sulfurized, or alkylated to give the ...