Rhodium(II)‐Catalyzed Selective C(sp³)−H Amination of Alkanes

Abstract

The development of an efficient catalytic system enabling the conversion of alkanes to valuable nitrogen‐containing building blocks is reported. Light alkanes can be selectively functionalized by an intermolecular C(sp3)−H amination reaction that proceeds at room temperature in the presence of only 1 mol % of a dirhodium(II) complex. Selective amination of tertiary C(sp3)−H within acyclic or cyclic alkanes used as limiting components leads to the corresponding amides isolated with yields in the 51–96 % range. The reaction, that can be performed on a gram‐scale, applies with equal levels of efficiency and selectivity to more complex hydrocarbons.

Mechanistic Insights into the Origins of Selectivity in a Cu-Catalyzed C–H Amidation Reaction

“…Selective reactions of unactivated C­(sp 3 )–H bonds enable rapid diversification of a wide range of compounds. − In particular, methods for the amination of alkyl C–H bonds have the potential to provide direct access to N -alkyl amine derivatives in complex molecules or high-performance materials without the need for a preinstalled, reactive functional group. , Significant progress has been made toward the development of catalytic, intermolecular C–H aminations that involve metallacyclic, metal-nitrenoid, or free-radical intermediates (Figure a), but most methods require activated C–H bonds or rely on directing groups to achieve the desired selectivity. − Undirected aminations of tertiary and benzylic C­(sp 3 )–H bonds have been accomplished by metal-nitrenoid intermediates, − but reactions at secondary C–H bonds and analogous transformations involving free-radical intermediates with high yields and regioselectivity remain challenging to achieve.…”