Stereoselective Multicomponent Reactions Using Zincate Nucleophiles: β-Dicarbonyl Synthesis and Functionalization

A general strategy for conjugate addition-C-acylation that enables the synthesis of enantioenriched β-dicarbonyl compounds is described. A novel method for derivatizing these adducts by stereo- and site-selective zinc-catalyzed addition of alkyllithium reagents is also reported. These reactions can be performed in tandem to achieve an enantio- and diastereoselective four-component coupling. The in situ generation of weakly basic lithium zincate species is central to the success of all three transformations.