Nickel-catalysed anti-Markovnikov hydroarylation of unactivated alkenes with unactivated arenes facilitated by non-covalent interactions

Alkyl halides as both hydride and alkyl sources in catalytic regioselective reductive olefin hydroalkylation

“…In contrast, reactions with unactivated aliphatic C=C bonds are typically plagued by lower substrate reactivity and/or poorer regiochemical differentiation leading to unsatisfactory levels of site selectivity. Notwithstanding these difficulties, remarkable advances for both anti-Markovnikov [18][19][20][21][22][23][24][25] (linear)-and Markovnikov [26][27][28][29][30] (branched)-selective hydroarylations of alkyl-substituted alkenes have been made. A single report on Pd-catalyzed olefin hydroalkynylation/hydroalkenylation to afford linear products was also recently disclosed 31 .…”

Direct C(sp2)–H alkylation of unactivated arenes enabled by photoinduced Pd catalysis

“…Recently, Hartwig and Nakao succeeded in the development of a hydroarylation reaction of unactivated arenes with alkenes in high linear/branched selectivities (>50:1). This reaction was catalyzed by a Ni complex bearing a highly sterically bulky N -heterocyclic carbene (NHC) ligand 8 . However, the reaction is not applicable to polar functional groups, such as nitriles and esters, due to limited functional group tolerance 9 .…”

Oxidative Alkenylation of Arenes Using Supported Rh Materials: Evidence that Active Catalysts are Formed by Rh Leaching

“… [3,9–11] Although EB/SM and PO/SM processes have been commercialized, existing industrial processes for styrene and alkyl arene syntheses have some disadvantages, including: 1) multi‐step processes; for example, the EB/SM process includes benzene alkylation, transalkylation, and ethylbenzene dehydrogenation, while the PO/SM process involves benzene alkylation, ethylbenzene oxidation, oxygen transfer, and dehydration; 2) energy‐intensive operations such as trans‐alkylation and distillation; and 3) the inability to produce anti‐Markovnikov products ( i.e ., 1‐aryl alkenes or alkanes) [12] . Thus, there is increased interest in developing new catalytic processes for direct arene alkenylation at a low operating temperature that offer anti‐Markovnikov selectivity [13–15] …”

“… [14,16–20] These potential advantages include: a) direct arene alkenylation (rather than alkylation) via β‐hydride elimination after the olefin insertion step, b) selective production of 1‐aryl alkane/alkene by circumventing carbocationic intermediates that lead to Markovnikov selectivity, c) conversion of electron‐deficient arenes, d) new regioselectivity for alkenylation or alkylation of substituted arenes, and e) inhibition of polyalkylation since alkylated or alkenylated products can be less reactive than starting arenes [14] . Molecular catalysts involving Ni, Ir, Ru, Pt, Pd and Rh have been studied for catalytic C−H alkylation or alkenylation of arenes with α‐olefins [15,16,21–35] …”

“…[12] Thus, there is increased interest in developing new catalytic processes for direct arene alkenylation at a low operating temperature that offer anti-Markovnikov selectivity. [13][14][15] Transition metal-catalyzed arene alkenylation (i.e., oxidative olefin hydroarylation) that functions by a pathway involving arene CÀ H activation and olefin insertion offers possible advantages over traditional acid-catalyzed arene alkylation (Scheme 2). [14,[16][17][18][19][20] These potential advantages include: a) direct arene alkenylation (rather than alkylation) via β-hydride elimination after the olefin insertion step, b) selective production of 1-aryl alkane/alkene by circumventing carbocationic intermediates that lead to Markovnikov selectivity, c) conversion of electron-deficient arenes, d) new regioselectivity for alkenyla-tion or alkylation of substituted arenes, and e) inhibition of polyalkylation since alkylated or alkenylated products can be less reactive than starting arenes.…”