Iron-Catalyzed Asymmetric Reductive Cross-Coupling of Ketimines with Alkyl Iodides

We report herein an Fe-catalyzed asymmetric reductive cross-coupling of carbonyl-containing ketimines with unactivated alkyl halides, enabling the efficient synthesis of enantioenriched α-tertiary amino esters and amides. This transformation is promoted by a commercially available iron(II) triflate catalyst in combination with a chiral bisoxazoline-phosphine (NPN) ligand and inexpensive manganese as the reductant. A broad range of primary and secondary alkyl iodides are compatible, affording the desired products in high yields with excellent enantioselectivities and exceptional functional group tolerance. The protocol is amenable to the late-stage decoration of complex molecules and the construction of heterocycles bearing quaternary stereocenters. Mechanistic investigations, including radical clock experiments and high-resolution mass spectrometry, support a single-electron-transfer (SET) pathway involving Fe(I)/Fe(II)/Fe(III) redox cycling and alkyl radical species. This work not only expands the toolbox for asymmetric C(sp³)-C bond formation but also showcases the untapped potential of chiral iron catalysis in stereoselective radical transformations.