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.