The behavior of 2-substituted-1,3-diphenylpropane-1,3-tione toward organophosphorus reagents

The reaction of 2-benzylidene-1,3-diphenylpropanetrione (1a) with phosphoru s ylides 2a-c afforded the new phosphonium ylides 4a-c. Trialkyl phosphites 3a-c react with 1a to give the respective dialkyl phosphonate products 5a- c. On the other hand the olefinic compounds 6 and 7 were isolated from the reaction of 1b with Wittig reagents 2. Moreover, trialkyl phosphites reacte d with 1b to give products 8a-c. Possible reaction mechanisms are considere d, and the structural assignments ave based on analytical and spectroscopic evidence. (C) 2000 John Wiley & Sons, Inc.