Palladium-catalyzed coupling of ammonia with aryl chlorides, bromides, iodides, and sulfonates: a general method for the preparation of primary arylamines.
We report that the complex generated from Pd[P(o-tol)(3)](2) and the alkylbisphosphine CyPF-t-Bu is a highly active and selective catalyst for the coupling of ammonia with aryl chlorides, bromides, iodides, and sulfonates. The couplings of ammonia with this catalyst conducted with a solution of ammonia in dioxane form primary arylamines from a variety of aryl electrophiles in high yields. Catalyst loadings as low as 0.1 mol % were sufficient for reactions of many aryl chlorides and bromides. In the presence of this catalyst, aryl sulfonates also coupled with ammonia for the first time in high yields. A comparison of reactions in the presence of this catalyst versus those in the presence of existing copper and palladium systems revealed a complementary, if not broader, substrate scope. The utility of this method to generate amides, imides, and carbamates is illustrated by a one-pot synthesis of a small library of these carbonyl compounds from aryl bromides and chlorides, ammonia, and acid chlorides or anhydrides. Mechanistic studies show that reactions conducted with the combination of Pd[P(o-tol)(3)](2) and CyPF-t-Bu as catalyst occur with faster rates and higher yields than those conducted with CyPF-t-Bu and palladiun(II) as catalyst precursors because of the low concentration of active catalyst that is generated from the combination of palladium(II), ammonia, and base.
Vo
Giang D
GD
Department of Chemistry, University of Illinois, 600 South Mathews Avenue, Urbana, Illinois 61801, USA.
Hartwig
John F
JF
D000588:Amines / Q000138:chemical synthesis*; D000641:Ammonia / Q000737:chemistry*; D001190:Arylsulfonates / Q000737:chemistry; D001965:Bromides / Q000737:chemistry; D002384:Catalysis; D002712:Chlorides / Q000737:chemistry; D007454:Iodides / Q000737:chemistry; D008722:Methods; D055601:Organic Chemistry Phenomena; D010165:Palladium / Q000737:chemistry*
D000588:Amines; D001190:Arylsulfonates; D001965:Bromides; D002712:Chlorides; D007454:Iodides; D010165:Palladium; D000641:Ammonia