Direct Conjugate Addition of Alkynes with α,β-Unsaturated Carbonyl Compounds Catalyzed by NCN-Pincer Ru Complexes

NCN‐pincer Ru‐complexes containing bis(oxazolinyl)phenyl ligands serve as suitable catalysts in the direct conjugate additions of α,β‐unsaturated carbonyl compounds, including ketones, esters, and amides, as well as vinylphosphonates, giving various β‐alkynyl carbonyl and phosphonate compounds. A bis(oxazolinyl)phenyl (phebox)–Ru complex also catalyzes the asymmetric conjugate addition of an alkyne with a β‐substituted, α,β‐unsaturated ketone to produce a chiral β‐alkynyl ketone. Thinking outside the phebox: NCN‐pincer Ru complexes containing bis(oxazolinyl)phenyl ligands (phebox) serve as suitable catalysts in the direct conjugate additions of α,β‐unsaturated carbonyl compounds, including ketones, esters, and amides, as well as vinylphosphonates, to give various β‐alkynyl carbonyl and phosphonate compounds (see scheme).