Conjugate addition-enantioselective protonation to forge tertiary stereocentres α to azaarenes via cooperative hydrogen atom transfer and chiral hydrogen-bonding catalysis
Cooperative hydrogen atom transfer and chiral hydrogen-bonding catalysis as a new platform for the asymmetric synthesis of azaarene derivatives is reported. By using a tetrabutylammonium decatungstate as the photocatalyst and a chiral phosphoric acid as the hydrogen-bonding catalyst, transformations of a variety of commercially available hydrocarbons and silanes with diverse α-branched 2-vinylazaarenes
The direct alpha-methylenation of benzylpyridines was achieved using N,N-dimethylacetamide (DMA) as a one-carbon source under copper catalysis. An intermediary species was detected at an early stage, and a possible mechanism was proposed. Additionally, alpha-oxygenation and dimerization of benzylpyridines could also be performed efficiently.