Manganese-Mediated C–C Bond Formation: Alkoxycarbonylation of Organoboranes

Abstract

Alkoxycarbonylations are important and versatile reactions that result in the formation of a new C–C bond. Herein, we report on a new and halide-free alkoxycarbonylation reaction that does not require the application of an external carbon monoxide atmosphere. Instead, manganese carbonyl complexes and organo(alkoxy)borate salts react to form an ester product containing the target C–C bond. The required organo(alkoxy)borate salts are conveniently generated from the stoichiometric reaction of an organoborane and an alkoxide salt and can be telescoped without purification. The protocol leads to the formation of both aromatic and aliphatic esters and gives complete control over the ester’s substitution (e.g., OMe, O t Bu, OPh). A reaction mechanism was proposed on the basis of stoichiometric reactivity studies, spectroscopy, and DFT calculations. The new chemistry is particularly relevant for the field of Mn(I) catalysis and clearly points to a potential pathway toward irreversible catalyst deactivation.

ReNeGate: Reaction Network Graph Theoretical tool for automated mechanistic studies in computational homogeneous catalysis

“…This new reactivity insight has been verified experimentally and inspired the development of new Mn-mediated C-C coupling chemistry recently reported by our group. 36 In line with earlier experimental studies, the automated procedure predicts that further migratory insertion of the CO ligand with the -C(O)OiPr α-ketoacyl species is thermodynamically strongly unfavorable 38 . The resulting C-Mn α-ketoacyl conformers (III) and (IV) are ca.…”

“…The capabilities of the proposed methodology have been validated for the dehydrogenation reaction of manganese pentacarbonyl bromide (Mn(CO)5Br) 36 and N,N′-Dimethyl-1,2cyclohexanediamino manganese tricarbonyl bromide (MnBr(CO)3NN) precatalysts. The presented automated reaction network analysis successfully reveals the experimentally observed major reaction channels and also helps identifying the more challenging minor reaction paths, that can be initiated by the catalyst activation procedure and open paths to long-term catalyst deactivation.…”

“…For the first case study, we considered the transformations of Mn(CO)5Br complex in an alkoxide base solutions simulating a common catalyst activation procedure (Figure 4a). 36 A minimal model containing Mn(CO)5Br and KOiPr species was considered here. Parallel metadynamics simulations were carried out using the CREST functionality in the GFN2-xTB method where the pushing and pulling strengths (k and α) were systematically varied over the parallel simulations.…”

Polyoxometalate-like structure of new potassium triphenylsiloxides: [K6(OSiPh3)6(C3H7OH)(H2O)]·2C6H5CH3 and [K6(OSiPh3)6(H2O)2]

“…Moreover, in 1, there are interactions between the K atoms and the O atoms of the propan-2-ol molecule; these are the K2-O1U, K3-O1U and K6-O1U bonds, with lengths of 2.890 (3), 2.780 (3) and 2.974 (3) Å , respectively. Similar bonds between the K atom and the non-deprotonated hydroxy group of propan-2-ol occur in the [K 2 (VO) 2 (C 3 H 7 O) 6 -(C 3 H 7 OH) 2 ] coordination entity (van Putten et al, 2021), where each of the metal atoms is bound to one alcohol molecule. The lengths of these bonds are 2.666 (2) and 2.607 (3) Å , respectively.…”

Green Chemistry and Process Intensification: Milestones on a Sustainable Development

“…Researchers worked on cobalt [70] and iron [71] catalysts for hydrosilylation and nickel precursors and heterogeneous catalysts for Suzuki−Miyaura coupling, one of the most largely employed processes for C−C bond generation. Further, Van Putten, et al [72] observed the role of manganese in mediating C−C bond generation from organoboranes.…”