Baylis–Hillman reactions of N-arylidenediphenylphosphinamides with methyl vinyl ketone, methyl acrylate, and acrylonitrile

We have found that in the Baylis–Hillman reactions of N-arylidenediphenylphosphinamides 1 with methyl vinyl ketone (MVK), methyl acrylate or acrylonitrile, the Lewis base and solvent can significantly affect the reaction rate. Using PPh3 as Lewis base in the reaction of 1 with MVK in DMF, THF or MeCN, the normal Baylis–Hillman adduct 2 was formed in very high yield. In the Baylis–Hillman reaction of 1 with methyl acrylate, the Lewis base Ph2PMe must be used in order to get a high yield of the Baylis–Hillman adduct 3. On the other hand, for the reaction of N-arylidenediphenylphosphinamides 1 with acrylonitrile, DABCO is the best Lewis base giving the corresponding Baylis–Hillman adducts 4 in high yields.