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Ketone functionalization is a cornerstone of organic synthesis. Herein, we describe the development of an intermolecular C−H alkenylation of enamides with the feedstock chemical vinyl acetate to access diverse functionalized ketones. Enamides derived from various cyclic and acyclic ketones reacted efficiently, and a number of sensitive functional groups were tolerated. In this iridium‐catalyzed transformation, two structurally and electronically similar alkenes—enamide and vinyl acetate—underwent selective cross‐coupling through C−H activation. No reaction partner was used in large excess. The reaction is also pH‐ and redox‐neutral with HOAc as the only stoichiometric by‐product. Detailed experimental and computational studies revealed a reaction mechanism involving 1,2‐Ir‐C migratory insertion followed bysyn‐β‐acetoxy elimination, which is different from that of previous vinyl acetate mediated C−H activation reactions. Finally, the alkenylation product can serve as a versatile intermediate to deliver a variety of structurally modified ketones.

The development of a platinum‐catalyzed desaturation of cyclic ketones to their conjugated α,β‐unsaturated counterparts is reported in this full article. A unique diene‐platinum complex was identified to be an efficient catalyst, which enables direct metal‐enolate formation. The reaction operates under mild conditions without using strong bases or acids. Good to excellent yields can be achieved for diverse and complex scaffolds. A wide range of functional groups, including those sensitive to acids, bases/nucleophiles, or palladium species, are tolerated, which represents a distinct feature from other known desaturation methods. Mechanistically, this platinum catalysis exhibits a fast and reversible α‐deprotonation followed by a rate‐determining β‐hydrogen elimination process, which is different from the prior Pd‐catalyzed desaturation method. Promising preliminary enantioselective desaturation using a chiral‐diene‐platinum complex has also been obtained.

Herein, we describe an intermolecular direct branched‐selective α‐alkylation of cyclic ketones with simple alkenes as the alkylation agents. Through an enamine‐transition metal cooperative catalysis mode, the α‐alkylation is realized in an atom‐ and step‐economic manner with excellent branched selectivity for preparing β‐branched ketones. Employment of a pair of bulky Brønsted acid and base as additives is responsible for enhanced efficiency. Promising enantioselectivity (74 % ee) has been obtained. Experimental and computational mechanistic studies suggest that a pathway through alkene migratory insertion into the Ir−C bond followed by C−H reductive elimination is involved for the high branched selectivity.