Palladium-Catalyzed Difluorocarbene Transfer Enabled Divergent Synthesis of γ-Butenolides and Ynones from Iodobenzene and Terminal Alkynes

Abstract

Herein, we report a ligand-controlled palladiumcatalyzed method that enables the synthesis of ynones and γbutenolides with excellent regioselectivity from the same set of readily available aryl iodides, aryl acetylenes, and BrCF 2 CO 2 K. In this reaction, the [Pd II ]�CF 2 does demonstrate electrophilicity and can generate CO readily when reacting with H 2 O. It is environmentally friendly and safe compared to traditional methods, and the current protocol enables us to afford ynones and γbutenolides in high yields with excellent functionality tolerance. Moreover, esters can also be obtained with corresponding phenols and alcohols utilizing this strategy. The success of late-stage functionalization of bioactive compounds further illustrates the synthetic utility of this protocol in material development and drug discovery.

Switching from gem-difluorovinylation to carboxylation: ligand-enabled palladium-catalyzed Heck annulation of alkene-tethered aryl halides with sodium difluorochloroacetate

“…Difluoroacetate derivatives (XCF 2 COOR) are low-cost and widely available regents, which are usually used for the introduction of difluoroalkyl and carbonyl moieties. 17–20 On the one hand, tandem reactions triggered by difluoroalkyl radicals (˙CF 2 COOR) have been extensively studied. 21–23 On the other hand, with the action of a base, they can generate difluorocarbene and CO 2 through the cleavage of C–X and C–C bonds.…”