Carbonyls as Latent Alkyl Carbanions for Conjugate Additions

Angewandte Chemie - International Edition

5 years ago

Carbonyls as Latent Alkyl Carbanions for Conjugate Additions

Chao-Jun Li, Haining Wang, Xi-Jie Dai

Conjugate addition of carbon nucleophiles to electron-deficient olefins is one of the most powerful methods for forming carbon–carbon bonds. Despite great achievements in controlling the selectivity, variation of the carbon nucleophiles remains largely underexplored, with this approach relying mostly on organometallic reagents. Herein, we report that naturally abundant carbonyls can act as latent carbon nucleophiles for conjugate additions through a ruthenium-catalyzed process, with water and nitrogen as innocuous byproducts. The key to our success is homogeneous ruthenium(II) catalysis, combined with phosphines as spectator ligands and hydrazine as the reducing agent. This chemistry allows the incorporation of highly functionalized alkyl fragments into a vast array of electron-deficient olefins under mild reaction conditions in a reaction complementary to the classical organometallic-reagent-based conjugate additions mediated or catalyzed by “soft” transition metals. Hidden talents: Carbonyls can act as latent carbon nucleophiles for conjugate additions through a ruthenium-catalyzed process. The reaction relies on homogeneous ruthenium(II) catalysis combined with phosphines as spectator ligands and hydrazine as the reducing agent. This method enables the incorporation of highly functionalized alkyl fragments into a vast array of electron-deficient olefins under mild reaction conditions. EWG=electron-withdrawing grop

Publisher URL: http://onlinelibrary.wiley.com/resolve/doi

DOI: 10.1002/anie.201700059