A novel, manganese-catalyzed oxidative azidation of cyclobutanols is described. A wide range of primary, secondary, and tertiary alkyl azides were generated in synthetically useful yields and exclusive regioselectivity. Aside from linear alkyl azides, otherwise elusive medium-sized cyclic azides were also readily prepared. Preliminary mechanistic studies reveal that the reaction likely proceeds by a radical-mediated C-C bond cleavage/C-N3 bond formation pathway.

Herein we report a novel, general protocol for distal heteroaryl ipso-migration and its application to the elusive heteroarylation of unactivated alkenes. A set of nitrogen-containing heteroaryl groups showcase the migratory aptitude. This reaction provides a variety of fluoroalkyl functionalized heteroarenes under mild reaction conditions. This is the first report of a difunctionalization of unactivated alkenes with distal heteroaryl migration.

A direct enantioselective acylation of α-amino C(sp 3 )−H bonds with carboxylic acids has been achieved via the merger of transition metal and photoredox catalysis. This straightforward protocol enables cross-coupling of a wide range of carboxylic acids, one class of feedstock chemicals, with readily available N-alkyl benzamides to produce highly valuable α-amino ketones in high enantioselectivities under mild conditions. The synthetic utility of this method is further demonstrated by gram scale synthesis and application to late-stage functionalization. This method provides an unprecedented solution to address the challenging stereocontrol in metallaphotoredox catalysis and C(sp 3 )−H functionalization. Mechanistic studies suggest the α-C(sp 3 )−H bond of the benzamide coupling partner is cleavage by photocatalytically generated bromine radicals to form α-amino alkyl radicals, which subsequently engages in nickel-catalyzed asymmetric acylation.

Reported for the first time is a tertiary-alcohol-guided heteroarylation of remote C(sp )-H bonds. The mild and direct generation of alkoxyl radicals from alcohols is enabled by visible-light photocatalysis. A remote hydrogen atom and heteroaryl migration sequence are involved in the reaction. Many sensitive groups remain intact in the reaction, thus illustrating wide functional-group compatibility. This protocol provides a practical strategy for the late-stage modification of alkyl ketones.

Site- and enantioselective cross-coupling of saturated N-heterocycles and carboxylic acids—two of the most abundant and versatile functionalities—to form pharmaceutically relevant α-acylated amine derivatives remains a major challenge in organic synthesis. Here, we report a general strategy for the highly site- and enantioselective α-acylation of saturated N-heterocycles with in situ-activated carboxylic acids. This modular approach exploits the hydrogen-atom-transfer reactivity of photocatalytically generated chlorine radicals in combination with asymmetric nickel catalysis to selectively functionalize cyclic α-amino C−H bonds in the presence of benzylic, allylic, acyclic α-amino, and α-oxy methylene groups. The mild and scalable protocol requires no organometallic reagents, displays excellent chemo-, site- and enantioselectivity, and is amenable to late-stage diversification, including a modular synthesis of previously inaccessible Taxol derivatives. Mechanistic studies highlight the exceptional versatility of the chiral nickel catalyst in orchestrating (i) catalytic chlorine elimination, (ii) alkyl radical capture, (iii) cross-coupling, and (iv) asymmetric induction.