Experimental and computational insights into the mechanism of the copper(i)-catalysed sulfonylative Suzuki-Miyaura reaction

A mechanistic study into the copper(i)-catalysed sulfonylative Suzuki-Miyaura reaction, incorporating sulfur dioxide, is described. Utilising spectroscopic and computational techniques, an exploration into the individual components of the competing catalytic cycles is delineated, including identification of the resting state catalyst, transmetalation of arylboronic acid onto copper(i), the sulfur dioxide insertion process, and the oxidative addition of aryl halide to Cu^I. Studies also investigated prominent side-reactions which were uncovered, including a competing copper(ii)-catalysed mechanism. This led to an additional proposed and connected Cu^I/Cu^II/Cu^III catalytic cycle to account for by-product formation.

Weak Electrostatic Interactions with Bisphosphine Ligands Facilitate Reductive Elimination of PhCF3 from Pd(II) Complexes

The origins of ligand effects on PhCF₃ reductive elimination from Pd^II complexes were computationally investigated by using energy decomposition analysis. The results indicate weak electrostatic interactions between ligands and Ph-Pd-CF₃ lead to small barriers of PhCF₃ reductive elimination. Two major factors affecting the electrostatic interactions are identified.

Regiocontrolled synthesis of enantioenriched 2-substituted dehydropiperidines by stereospecific allyl-allyl cross-coupling of a chiral allylic boronate

The palladium-catalyzed cross-coupling of an optically enriched dehydropiperidinyl boronate with cinnamyl carbonates was optimized to minimize stereochemical erosion. Although the coupling of two unsymmetrical allyl fragments may generate four possible regioisomers, the optimal procedure using (p-CF₃C₆H₄)₃P as the ligand affords linear 2-allylated 3,4-dehydropiperidines exclusively (>98 : 2 rr) with enantiospecificity up to 99%.

Preliminary modelling as the first stage of targeted organic synthesis

The review aims to present a classification and applicability analysis of methods for preliminary molecular modelling for targeted organic, catalytic and biocatalytic synthesis. The following three main approaches are considered as a primary classification of the methods: modelling of the target – ligand coordination without structural information on both the target and the resulting complex; calculations based on experimentally obtained structural information about the target; and dynamic simulation of the target – ligand complex and the reaction mechanism with calculation of the free energy of the reaction. The review is meant for synthetic chemists to be used as a guide for building an algorithm for preliminary modelling and synthesis of structures with specified properties.

The bibliography includes 353 references.

Promoting Difficult Carbon-Carbon Couplings: Which Ligand Does Best?

A Pd complex, cis-[Pd(C₆ F₅ )₂ (THF)₂ ] (1), is proposed as a useful touchstone for direct and simple experimental measurement of the relative ability of ancillary ligands to induce C-C coupling. Interestingly, 1 is also a good alternative to other precatalysts used to produce Pd⁰ L. Complex 1 ranks the coupling ability of some popular ligands in the order P^t Bu₃ >o-TolPEWO-F≈tBuXPhos>P(C₆ F₅ )₃ ≈PhPEWO-F>P(o-Tol)₃ ≈THF≈tBuBrettPhos≫Xantphos≈PhPEWO-H≫PPh₃ according to their initial coupling rates, whereas their efficiency, depending on competitive hydrolysis, is ranked tBuXPhos≈P^t Bu₃ ≈o-TolPEWO-F>PhPEWO-F>P(C₆ F₅ )₃ ≫tBuBrettPhos>THF≈P(o-Tol)₃ >Xantphos>PhPEWO-H≫PPh₃ . This "meter" also detects some other possible virtues or complications of ligands such as tBuXPhos or tBuBrettPhos.

Diverse copper(iii) trifluoromethyl complexes with mono-, bi- and tridentate ligands and their versatile reactivity

Novel square planar (L)Cu^III(CF₃)₃ (L = pyridine, 2,4,6-trimethylpyridine) complexes, which are fluxional in solution and versatile to enable various transformations, are isolated and characterized for the first time.

Synthesis, Characterization, and Reactivity of Palladium Fluoroenolate Complexes

Cross-coupling reactions of aryl groups with α-fluoro carbonyl compounds catalyzed by palladium complexes have been reported, but palladium fluoroenolate intermediates relevant to such reactions have not been isolated or even detected previously. We report the synthesis, structural characterization, and reactivity of a series of C-bound arylpalladium fluoroenolate complexes ligated by monophosphines and bisphosphines. DPPF-ligated arylpalladium fluoroenolate complexes (DPPF = 1,1-bis(diphenylphosphino)-ferrocene) derived from a monofluoroester, a difluoroester, difluoroamides, and difluoroacetonitrile underwent reductive elimination in high yields. Reductive elimination was faster from complexes containing less electron-withdrawing fluoroenolate groups and longer Pd-C(enolate) bonds than from complexes containing more electron-withdrawing fluoroenolate groups and shorter Pd-C(enolate) bonds. The rates of reductive elimination from these C-bound fluoroenolate complexes were significantly faster than those of the analogous trifluoromethyl complexes.

Synthesis and reductive elimination of arylPd(ii) trifluoromethyl complexes: a remarkable concentration effect on chemoselectivity

A remarkable and unprecedented concentration effect on chemoselectivity is observed for the thermal decomposition of Pd(ii) aryl trifluoromethyl complexes. As the concentration increases, the Ar–CF₃ cross-coupling is suppressed gradually whilst the Ar–Ar homocoupling increases steadily.

An explicit account of solvation is essential for modeling Suzuki–Miyaura coupling in protic solvents

We compared explicit and implicit solvation approaches in modeling the free energy profile of the final step of Suzuki–Miyaura coupling.

Mechanisms and stereoselectivities of the Rh(i)-catalyzed carbenoid carbon insertion reaction of benzocyclobutenol with diazoester

Mechanisms and stereoselectivities of a Rh(i)-catalyzed carbenoid carbon insertion reaction of benzocyclobutenol with diazoester have been investigated using the DFT method.