Developing transition-metal catalysts for the intramolecular hydroamination of alkynes

Group 7-12 transition-metal complexes serve as effective catalysts for the regioselective intramolecular hydroamination of aminoalkynes having the gen eral,formula RC=C(CH2)(n)-NH2 (n = 3, R = H, Ph; n = 4, R = H) and of 2-(ph enylethynyl) aniline. Primary pro ducts are pyrrolidines and piperidines be aring an alpha-alkylidene functionality and 2-phenylindole, respectively. I somerization yields the corresponding pyrrolines and 1,2-dehydropiperidines . The catalytic properties of the transition-metal complexes depend on the appropriate choice of ligand, solvent, temperature, and counteranion. Princ iples for identifying the most active transition-metal catalysts for the hy droamination of alkynes and for optimizing the reaction conditions are deve loped. The X-ray crystal structure of one catalyst, [PdCl(triphos)](CF3-SO3 ), has been determined.