Site‐Differentiated Polyboron Arenes Prepared by Direct CH Borylation and Their Highly Selective Suzuki–Miyaura Cross‐Coupling Reactions

Abstract

Di- and polyboron (hetero)arenes, site-differentiated with MIDA boronyl (MIDA=N-methyliminodiacetic acid) and pinacolato boronyl (Bpin), were prepared by an iridium-catalyzed direct CH borylation of readily available (hetero)aryl MIDA boronates. The excellent synthetic uses of these multisite nucleophiles were demonstrated by the high-yield production of a variety of multifunctionalized poly(hetero)arenes with the highly chemoselective Suzuki-Miyaura coupling (SMC) of the Bpin moiety being an essential step.

Alkali metal mediated C–C bond coupling reaction

“…[1][2][3][4][5] Especially, the cross-coupling reactions have provided a great impetus to modern organic synthesis. According to the proposed mechanisms of these cross-coupling reactions, 6-10 the reaction is initiated by the oxidative insertion of palladium (0) into a carbon-halogen bond of the aryl halide used as substrate and forming a palladium (II) intermediate.…”

Enantioselective Borylation of Aromatic C−H Bonds with Chiral Dinitrogen Ligands

“…[1] Among various reactions that form C-B bonds, the direct borylation of aromatic C-H bonds catalyzed by transition metals is particularly valuable. [2], [3] The borylation occurs under mild conditions with high functional group compatibility. The reactions of arenes occur at the least sterically hindered aromatic C-H bond (Scheme 1a).…”

“…Because rhodium complexes containing phosphines also catalyze the borylation of aromatic C-H bonds, [3c, 4d] we tested various combinations of rhodium precursors and chiral phosphines as catalyst for the enantioselective borylation (for details, see Supporting Information). However, no conversion was observed for reactions conducted with any of the rhodium catalysts generated from [Rh(cod)Cl] 2 and chiral bisphosphine ligands.…”

Boryl (Hetero)aryne Precursors as Versatile Arylation Reagents: Synthesis through CH Activation and Orthogonal Reactivity

“…[11] Thev ersatility of aryl boronates and ortho-silyl aryl triflates renders the prospect of their selective postfunctionalization exceptionally attractive.I tp romises greatly to broaden the range of possible derivatives,o bviate tedious/ inefficient de novo syntheses,and enable iterative approaches to their elaboration. [12] However, the same mild and versatile reactivity that imparts aryl boronates and ortho-silyl aryl triflates with such broad appeal makes their postfunctionalization commensurately more challenging.Foraryl boronates,responses to this problem have largely relied on the use of protecting groups to mitigate the reactivity of the boron center with respect to that of (pseudo)halide, [13] stannane, [14] or orthogonally protected boronate [15] groups present on the same arene.H owever, this approach has been exploited almost exclusively in CÀC bond coupling;m ethods to introduce other valuable functionality remain scarce. [16] Remarkably,t he postfunctionalization of ortho-silyl aryl triflates has never been reported, despite their growing popularity and the passing of three decades since the seminal report by Kobayashi and co-workers on their use as aryne precursors.…”

“…Foraryl boronates,responses to this problem have largely relied on the use of protecting groups to mitigate the reactivity of the boron center with respect to that of (pseudo)halide, [13] stannane, [14] or orthogonally protected boronate [15] groups present on the same arene.H owever, this approach has been exploited almost exclusively in CÀC bond coupling;m ethods to introduce other valuable functionality remain scarce. [16] Remarkably,t he postfunctionalization of ortho-silyl aryl triflates has never been reported, despite their growing popularity and the passing of three decades since the seminal report by Kobayashi and co-workers on their use as aryne precursors.…”