Synthesis of Diverse P,N-Containing Heterocycles

Significance

Reported here is the formation of various P,N heterocycles via the Pudovik or ­Kabachnik-Fields reaction to form a P-C bond, followed by cyclization through displacement of a halide. In the first two cases shown above, cyclization was achieved simply through an intramolecular S_N2 reaction, and in the lower three examples Buchwald-Hartwig and Heck cross-coupling chemistry was used. Interestingly, the C-N cross-coupling could be achieved without using the more sophisticated Buchwald-Hartwig-type ligands.