Selective carbon–carbon bond activation is important in chemical industry and fundamental organic synthesis, but remains challenging. In this study, non-polar unstrained Csp2–Csp3 and Csp2–Csp2 bond activation was achieved by B(OMe)3/B2pin2-mediated fragmentation borylation. Various indole derivatives underwent C2-regioselective C–C bond activation to afford two C–B bonds under transition-metal-free
Iron-Catalyzed C(sp<sup>2</sup>)–C(sp<sup>3</sup>) Suzuki–Miyaura Cross-Coupling Using an Alkoxide Base
作者:Paul O. Peterson、Matthew V. Joannou、Eric M. Simmons、Steven R. Wisniewski、Junho Kim、Paul J. Chirik
DOI:10.1021/acscatal.2c05838
日期:2023.2.17
The synthesis and characterization of phenoxy(imine) iron(II) alkyl precatalysts for C(sp2)–C(sp3) Suzuki–Miyaura cross-coupling of aryl boronic esters and alkyl bromides is described. Addition of phenoxyimines (FI) to (py)2Fe(CH2SiMe3)2 (py = pyridine) afforded the high-spin iron(II) alkylderivatives, (FI)Fe(CH2SiMe3)(py) with varying N-imine substituents. With both neopentyl glycol-protected (BNeo)
When the esters of arylboronic acids with 2,2-dimethylpropan-1,3-diol were treated with a catalytic amount of [Rh(OH)(cod)]2 in the presence of 1,3-bis(diphenylphosphino)propane and CsF in dioxane at 60 degrees C under carbon dioxide atmosphere, the benzoic acid derivatives were obtained in good yields. Reactions of alkenylboronic esters also proceeded under similar conditions to give alpha,beta-unsaturated carboxylic acids. As these boronic esters are now easily available through coupling or direct borylation reactions, this method would be a useful method for the preparation of various functionalized aryl- and alkenyl-carboxylic acids.
Mechanism and Scope of Nickel-Catalyzed Decarbonylative Borylation of Carboxylic Acid Fluorides
作者:Christian A. Malapit、James R. Bour、Simon R. Laursen、Melanie S. Sanford
DOI:10.1021/jacs.9b08961
日期:2019.10.30
Article describes the development of a base-free, nickel-catalyzeddecarbonylative coupling of carboxylic acid fluorides with diboron reagents to selectively afford aryl boronate ester products. Detailed studies were conducted to assess the relative rates of direct transmetalation between aryl boronate esters and diboron reagents and a bisphosphine nickel(aryl)(fluoride) intermediate. These investigations
Cobalt-Catalyzed C(sp<sup>2</sup>)–C(sp<sup>3</sup>) Suzuki–Miyaura Cross-Coupling Enabled by Well-Defined Precatalysts with L,X-Type Ligands
作者:L. Reginald Mills、David Gygi、Jacob R. Ludwig、Eric M. Simmons、Steven R. Wisniewski、Junho Kim、Paul J. Chirik
DOI:10.1021/acscatal.1c05586
日期:2022.2.4
Cobalt(II) halides in combination with phenoxyimine (FI) ligands generated efficient precatalysts in situ for the C(sp2)–C(sp3) Suzuki–Miyaura cross-coupling between alkyl bromides and neopentylglycol (hetero)arylboronic esters. The protocol enabled efficient C–C bond formation with a host of nucleophiles and electrophiles (36 examples, 34–95%) with precatalyst loadings of 5 mol %. Studies with alkyl