Four-coordinate triarylborane synthesis via cascade B–Cl/C–B cross-metathesis and C–H bond borylation

Abstract

We herein describe a tandem highly selective B–Cl/C–B cross-metathesis of two same or different arylboranes and C–H bond borylation to synthesize four-coordinate triarylboranes with broad substrate scope.

Pyrimidine-directed metal-free C–H borylation of 2-pyrimidylanilines: a useful process for tetra-coordinated triarylborane synthesis

“…7d Proton abstraction by a base then gives the dibromoboron complex 1c, which, upon quenching with pinacol and triethyl amine, provides the desired borylated product 1b. The results of 11 B NMR experiments suggest that electrophilic borylation proceeds soon after a borenium species 51 is generated from the adduct 50, because of the electron-rich nature of 2-pyrimidylaniline. However, the possibility that a base accelerates disproportionation between 50 and BBr 3 cannot be excluded.…”

“…One of the more recent strategies is cascade B-Cl/C-B cross metathesis and C-H bond borylation. 11 While this strategy is interesting, it has some drawbacks, including the need for harsh conditions, the production of various waste by-products, and relatively poor yields of triarylboranes. Therefore, the most attractive strategy would involve the use of boron trihalide to construct tetracoordinated fluorophores via activating a C-H bond using a directing atom of a heterocycle.…”

Catalytic Atroposelective Catellani Reaction Enables Construction of Axially Chiral Biaryl Monophosphine Oxides

“…To validate the feasibility of our conjecture and continue our long-term interest in boron chemistry, [58][59][60][61][62][63] 1-iodonaphthalene (1a), (2-bromo-3-methylphenyl)diphenylphosphine oxide (2a), and phenylboronic acid were first chosen as model substrates for the assembly of axially chiral monophosphine oxides. First, enantiopuresubstituted NBEs were prepared according to literature procedures 50,51 ; unfortunately, after careful condition screening (see Supporting Information Table S1 for details), only n-propyl ester NBE L3 demonstrated reactivity to deliver the desired axially chiral product in 57% NMR yield (48% isolated yield) with 98% ee, due to various Suzuki reaction side products (see Supporting Information for details).…”

B←N Coordination: From Chemistry to Organic Photovoltaic Materials

“…Fusing the B←N bonds symmetrically into the conjugated systems through electrophilic borylation creates B←N‐bridged units with ladder‐type and coplanar backbones. Several synthetic methodologies have been developed for electrophilic borylation, [ 71–76 ] which tends to occur on aromatic cycles, hydroxyl, or amine groups, producing C–B←N, O–B←N, or N–B←N‐bridged units, respectively ( Figure ). The substituents (X) on the B centers can be halos, Ph, Mes, or C 6 F 5 .…”