Regioselective Pt(II)‐Catalyzed 1,4‐Hydrosilylation of α,β‐Unsaturated Enamides and Tandem Carboxylation With CO 2

The regioselective hydrosilylation of α,β‐unsaturated carbonyl compounds remains a significant challenge, as multiple reaction pathways are possible, leading to products derived from hydrosilylation of either the C═C or the C═O double bond, or reduction of the carbonyl moiety. Strategies enabling selective 1,4‐hydrosilylation reactions that afford N , O ‐silyl ketene acetals from α,β‐unsaturated enamides are very rare. This is likely due, besides the previously mentioned regioselectivity problems, to the highly nucleophilic character of these molecules, which can undergo Michael‐type additions with the starting material. Indeed, these species are typically obtained through stoichiometric approaches. We have developed a catalytic protocol for the regioselective 1,4‐hydrosilylation of α,β‐unsaturated enamides using bench stable, low‐electron count platinum complexes [Pt(GePh 3 )(I t BuR) 2 )][BAr F ]. The reaction proceeds under mild conditions and exhibits broad functional‐group tolerance, including non‐conjugated carbonyl fragments and double bonds that remain intact. Notably, the use of an α,β‐unsaturated dienamide enables control over the regioselectivity, allowing the reaction to be steered toward a 1,6‐hydrosilylation pathway. Importantly, the N , O ‐silyl ketene acetals readily undergo reaction with CO 2 under mild reaction conditions leading to α‐carboxylated amides. This latter process takes place without the need of the catalyst. The tandem hydrosilylation/carboxylation reaction occurs with complete atom economy, highlighting its synthetic efficiency and sustainability.