Catalyst‐Controlled 1,2‐ and 1,1‐Arylboration of α‐Alkyl Alkenyl Arenes

Abstract

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Migratory Arylboration of Unactivated Alkenes Enabled by Nickel Catalysis

“…[19] Gratifyingly,s lightly changing the ratio of starting materials increased the yield to 83 %( entry 9). [8] Phosphine ligands,s uch as tricyclohexylphosphine (L8;e ntry 8) were also examined in this three-component transformation, but proved to be ineffective.I nterestingly,t he 1,3-arylboration product could also be generated when the reaction was conducted under an oxygen atmosphere (entry 10). [8] Phosphine ligands,s uch as tricyclohexylphosphine (L8;e ntry 8) were also examined in this three-component transformation, but proved to be ineffective.I nterestingly,t he 1,3-arylboration product could also be generated when the reaction was conducted under an oxygen atmosphere (entry 10).…”

“…[2] Great advances have been achieved in alkene 1,2-arylborations [3] with an elegant dual metal cooperative catalysis [4] reported by Semba and Nakao and Brown (Figure 1a,l eft). [8] Herein, we report the first nickel-catalyzed, regioselective arylboration of unactivated terminal alkenes,d elivering 1,ndifunctionalized (n > 2) products ( Figure 1b). [8] Herein, we report the first nickel-catalyzed, regioselective arylboration of unactivated terminal alkenes,d elivering 1,ndifunctionalized (n > 2) products ( Figure 1b).…”

Migratory Arylboration of Unactivated Alkenes Enabled by Nickel Catalysis

“…[5,6] However,u nactivated terminal alkenes are still challenging targets in 1,2-arylboration reactions.I n recent years,e fforts have also been devoted to the investigation of alkene arylborations involving metal migration, [7] but only limited examples on 1,1-arylborations by palladium migration have been reported to date (Figure 1a,r ight). [8] Herein, we report the first nickel-catalyzed, regioselective arylboration of unactivated terminal alkenes,d elivering 1,ndifunctionalized (n > 2) products ( Figure 1b). [9] Accordingly, an array of diarylsubstituted alkylboronic esters are prepared, and they are valuable synthons and an important pharmacophores in many drugs and other biologically relevant molecules (see Table S1 in the Supporting Information).…”

“…Notably,t he 1,1difunctionalized product 6a was selectively formed when 1,10-phenanthroline-4,7-diol (L7)was used (entry 7). [8] Phosphine ligands,s uch as tricyclohexylphosphine (L8;e ntry 8) were also examined in this three-component transformation, but proved to be ineffective.I nterestingly,t he 1,3-arylboration product could also be generated when the reaction was conducted under an oxygen atmosphere (entry 10). Furthermore,o ther commonly used diboron reagents were also examined in this three-component reaction (entries [11][12][13], and B 2 neo 2 (3b), B 2 hex 2 (3c), and B 2 cat 2 (3d)p roved to be suitable for the migratory difunctionalization reaction.…”

Recent advances in Cu-catalyzed C(sp3)–Si and C(sp3)–B bond formation

“…The selective arylborylation of α-alkylstyrenes 387 has been investigated, delivering 1,1-adducts 389, 390 in the presence of palladacycle PCy 3 Pd G3, while 1,2-adducts 391-393 result using APhosPd G3. The former reaction proceeds through a second-stage β-hydride elimination/re-insertion pathway, although for the latter set of conditions, a rare cross-coupling takes place (Scheme 62) [115].…”