Olefins devoid of directing or activating groups have been dicarbofunctionalized here with two electrophilic carbon sources under reductive conditions. Simultaneous formation of one C(sp 3 )−C(sp 3 ) and one C(sp 3 )−C(sp 2 ) bond across a variety of unbiased π-systems proceeds with exquisite selectivity by the combination of a Ni catalyst with TDAE as sacrificial reductant. Control experiments and computational studies revealed the feasibility of a radical-based mechanism involving, formally, two interconnected Ni(I)/Ni(III) processes and demonstrated the different ability of Ni(I) species (Ni(I)I vs PhNi(I)) to reduce the C(sp 3 )−I bond. The role of the reductant was also investigated in depth, suggesting that a oneelectron reduction of Ni(II) species to Ni(I) is thermodynamically favored. Further, the preferential activation of alkyl vs aryl halides by ArNi(I) complexes as well as the high affinity of ArNi(II) for secondary over tertiary C-centered radicals explains the lack of undesired homo-and direct coupling products (Ar−Ar, Ar−Alk) in these transformations.

To expand the scope of meta-functionalization, a pyrimidine-based template effective for the formation of β-aryl aldehydes and ketones, using allyl alcohols, by meta-C-H activation of benzylsulfonyl esters is described. In addition, α,β-unsaturated aldehydes were generated by in situ olefination and deprotection of allyl benzyl ethers. These new functionalizations at the meta-position of an arene have also been successfully implemented in benzylphosphonate, phenethyl carbonyl, and phenethylsulfonyl ester scaffolds. Key to these successful new functionalizations is the creation of an electropositive palladium center by accepting the electron cloud from the metal to the energetically low-lying π-orbitals of pyrimidine ring, and it favors coordination of allyl alcohol to the metal center.

The potential of merging photoredox and nickel catalysis to perform multicomponent alkene difunctionalizations under visible‐light irradiation is demonstrated here. Secondary and tertiary alkyl groups, as well as sulfonyl moieties can be added to the terminal position of the double bond with simultaneous arylation of the internal carbon atom in a single step under mild reaction conditions. The process, devoid of stoichiometric additives, benefits from the use of bench‐stable and easy‐to‐handle reagents, is operationally simple, and tolerates a wide variety of functional groups.

Palladium(II)‐catalyzed meta‐selective C−H allylation of arenes has been developed utilizing synthetically inert unactivated acyclic internal olefins as allylic surrogates. The strong σ‐donating and π‐accepting ability of pyrimidine‐based directing group facilitates the olefin insertion by overcoming inertness of the typical unactivated internal olefins. Exclusive allyl over styrenyl product selectivity as well as E stereoselectivity were achieved with broad substrate scope, wide functional‐group tolerance, and good to excellent yields. Late‐stage functionalisations of pharmaceuticals were demonstrated. Experimental and computational studies shed light on the mechanism and point to key steric control in the palladacycle, thus determining product selectivities.

An easily removable pyrimidine-based auxiliary has been employed for the remote meta-C-H cyanation of arenes. The scope of this Pd-catalyzed cyanation reaction using copper(I) cyanide as the cyanating agent was demonstrated with benzylsilanes, benzylsulfonates, benzylphophonates, phenethylsulfonates, and phenethyl ether derivatives. The method was utilized for the synthesis of pharmaceutically valuable precursors.