Ni-catalyzed hydroalkylation of olefins with N-sulfonyl amines

Catalytic addition of a carbon chain and a hydrogen across a double bond has often required an added hydride source. Here the authors show a method to add alkanes with an amino functionality to olefins, wherein a nickel catalyst uses the amine itself as the hydride source, obviating an external hydride reagent. Hydroalkylation, the direct addition of a C(sp(3))-H bond across an olefin, is a desirable strategy to produce valuable, complex structural motifs in functional materials, pharmaceuticals, and natural products. Herein, we report a reliable method for accessing alpha-branched amines via nickel-catalyzed hydroalkylation reactions. Specifically, by using bis(cyclooctadiene)nickel (Ni(cod)(2)) together with a phosphine ligand, we achieved a formal C(sp(3))-H bond insertion reaction between olefins and N-sulfonyl amines without the need for an external hydride source. The amine not only provides the alkyl motif but also delivers hydride to the olefin by means of a nickel-engaged beta-hydride elimination/reductive elimination process. This method provides a platform for constructing chiral alpha-branched amines by using a P-chiral ligand, demonstrating its potential utility in organic synthesis. Notably, a sulfonamidyl boronate complex formed in situ under basic conditions promotes ring-opening of the azanickellacycle reaction intermediate, leading to a significant improvement of the catalytic efficiency.

Automated summary

The authors demonstrate a method to add alkanes with an amino functionality to olefins using a nickel catalyst that utilizes the amine itself as the hydride source, eliminating the need for an external hydride reagent. This approach allows for the production of valuable, complex structural motifs and chiral alpha-branched amines in organic synthesis. Additionally, the use of a P-chiral ligand further enhances the catalytic efficiency of the reaction.