A One-Pot Synthesis of Pyranone and Pyrrole Derivatives from β-Chlorovinyl Ketones via Direct Conjugate Addition Approach.

The direct conjugate addition reactions of imino esters to β-chlorovinyl ketones have been accomplished in the presence of a substoichiometric amount of hard base, LiHMDS. An in situ generated species from the conjugate addition reaction readily acted as autocatalyst to convert the imino esters to its corresponding enolates. By utilizing a sequence of conjugate addition/elimination/lactonization followed by either reduction or reaction with amines, the novel one-pot syntheses of highly functionalized pyranone and pyrrole derivatives were accomplished in good to excellent yields.