Regioselective synthesis of 1,4,6-trisubstituted-2-pyridinones and 2,3-disubstituted (2H)-isoquinolin-1-ones via tandem Stille reaction/heterocyclisation

A general route to 1,4,6-trisubstituted 2-pyridinones and 2,3-disubstituted (2H)-isoquinolin-l-ones from (Z)-3-iodovinylic amides 1a-h and 2-iodo N-substituted benzamides 2a-f is described, including compounds bearing a substituent on the aromatic ring. Treatment of (Z)-beta-iodovinylic amides 1a-h and 2-iodobenzamides 2a-f with various allenyltributyltin reagents in the presence of palladium acetate, triphenylphosphine and tetrabutylammonium bromide in acetonitrile provided good yields of the corresponding 1,4,6-trisubstituted 2-pyridinones 3a-k and 2,3-disubstituted (2H)isoquinolin-l -ones 4a-i via tandem Stille reaction and 6-endo-dig azacyclisation.