Hydrate your chemistry! Hydrative cyclization of 5-yne-ynamides in the presence of Echavarren's catalyst and p-toluenesulphonic acid (PTSA)×H2O at room temperature affords an array of 1,6-dihydropyridin-2(3H)one derivatives. Isomerization, epoxidation, and hydrogenation of the double bond and insertion of an extended π-conjugate system into the pyridinone skeleton have been successfully accomplished (see scheme; Ts=tosyl).
- gold catalysis
- hydrative cyclization