Recent progress in nickel-catalyzed carboboration of alkenes

Abstract

Alkenes represent one of the most useful building blocks for organic synthesis, owing to their abundance and versatile reactivity. Transition metal (Pd, Cu, Co, Ni, Fe, etc.) catalyzed difunctionalization of...

Nickel-Catalyzed 1,1-Aminoborylation of Unactivated Terminal Alkenes

“…As for related Ni-catalyzed chain-walking reactions, we anticipated significant differences depending on the ligand employed. 8,9,24 As shown in entries 2− 5, this turned out to be the case. Intriguingly, however, ligands previously described to efficiently enable 1,1-difunctionalization 33 failed to provide significant amounts of 3a, whereas the utilization of electron-deficient olefin ligands provided the best results.…”

“…As expected, the solvent, temperature, nickel precatalyst, base, and concentration had a non-negligible impact on the reaction outcome (entries 6–10). As for related Ni-catalyzed chain-walking reactions, we anticipated significant differences depending on the ligand employed. ,, As shown in entries 2–5, this turned out to be the case. Intriguingly, however, ligands previously described to efficiently enable 1,1-difunctionalization failed to provide significant amounts of 3a , whereas the utilization of electron-deficient olefin ligands provided the best results. − Tentatively, this observation suggests that the presence of the latter might facilitate a final sp 3 C–N bond reductive elimination en route to 3a .…”

“…Such techniques not only offer a nonclassical site-selectivity pattern in the olefin functionalization arena but also provide a palette of conceptually new tactics for our ever-growing synthetic arsenal . Despite the elegant advances realized in C–C , and C–heteroatom bond-forming reactions, − the incorporation of two different heteroatom motifs across the olefin backbone with a 1,1-site-selectivity pattern still remains an underexplored, yet desirable, endeavor (Scheme ). , …”

Photoinduced Metal-Free Arylboration of Unactivated Alkenes: Synthesis of Indoline Boronic Ester

“…Furthermore, transition metal catalyzed 1,2-arylboration need to employ activated alkenes to increase the insertion rate before the direct reaction of aryl electrophiles such as aryl halides with boron nucleophiles. 14 In fact, unactivated alkenes are still challenging targets in 1,2-arylboration reactions. It is worth noting that Zhang et al demonstrated a Pd-catalyzed intramolecular cyclization of unactivated alkene to obtain indoline boronic esters up to 98% yield 15 .…”

Pd(0)-Catalyzed Diastereoselective and Enantioselective Intermolecular Heck–Miyaura Borylation of Internal Enamides for the β-Aminoboronate Ester Synthesis

“…Chiral organoboron compounds occupy paramount significance as fundamental building blocks with a broad spectrum of applications in organic synthesis and medicinal chemistry, which is not only attributed to the low toxicity but also because the C–B bond can be utilized as a versatile handle to access virtually all functional groups for value-added products synthesis. , Transition-metal-catalyzed enantioselective borylation has emerged as the most practical method to construct this skeleton, mainly including cross-coupling and C–H borylation, as well as hydroborylation and carboborylation of unsaturated hydrocarbons. , For instance, the employment of catalytic M–B species as nucleophiles, such as Cu–B, Pt–B, and Ni–B species, can undergo the stereoselective migratory insertion toward the alkene to forge the C–B bond, and the resulting C–M species can then react with external electrophiles. Additionally, the Pd­(II)-catalyzed Wacker-type anticarboborylation of alkenes also represents an important strategy for the synthesis of chiral organoboron compounds as independently developed by Engle and coworkers and by the Chen and He group .…”