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The dinuclear complex [Rh(μ‐Cl)(η2‐coe)(IPr)]2 is an efficient catalyst for the O‐selective Markovnikov‐type addition of 2‐pyridones to terminal alkynes. DFT calculations support a hydride‐free pathway entailing intramolecular oxidative protonation of a π‐alkyne by a κ1N‐hydroxypyridine ligand. Subsequent O‐nucleophilic attack on a metallacyclopropene species affords an O‐alkenyl‐2‐oxypyridine chelate rhodium intermediate as the catalyst resting state. The release of the alkenyl ether is calculated as the rate‐determining step. [ABSTRACT FROM AUTHOR]

New RhI-IPr (IPr = 1,3-bis(2,6-diisopropylphenyl)imidazolin-2-carbene) complexes bearing an N,O-pyridine-2-methanolato (N-O) bidentate ligand have been prepared. The carbonyl complex Rh(N-O)(IPr)(CO) efficiently catalyzes the hydrothiolation of a range of alkynes with high selectivity to α-vinyl sulfides. Reactivity studies and DFT calculations have revealed a new nonoxidative catalytic pathway, passing through RhI catalytic intermediates, which is driven by the interplay between the pyridine-2-methanolato and carbonyl ligands. The basic alkoxo ligand promotes the deprotonation of the thiol to generate the RhI active species, whereas the π-acceptor character of the carbonyl ligand hinders the oxidative addition process. In addition, the stereochemistry of the key thiolate-π-alkyne intermediate, which is determined by the electronic preference of the carbonyl ligand to coordinate cis to IPr, facilitates the rate-limiting alkyne thiometalation step. [ABSTRACT FROM AUTHOR]