Nickel Catalysts for the Dehydrative Decarbonylation of Carboxylic Acids to Alkenes

Electrochemical Decarboxylative Elimination of Carboxylic Acids to Alkenes

An electrochemical strategy for the decarboxylative elimination of carboxylic acids to alkenes at room temperature has been developed. This mild and oxidant-free method provides a green alternative to traditional thermal decarboxylation reactions. Structurally diverse aliphatic carboxylic acids, including biologically active drugs, underwent smooth conversion to the corresponding alkenes in good to excellent yields.

Scalable Electrochemical Decarboxylative Olefination Driven by Alternating Polarity

A mild, scalable (kg) metal-free electrochemical decarboxylation of alkyl carboxylic acids to olefins is disclosed. Numerous applications are presented wherein this transformation can simplify alkene synthesis and provide alternative synthetic access to valuable olefins from simple carboxylic acid feedstocks. This robust method relies on alternating polarity to maintain the quality of the electrode surface and local pH, providing a deeper understanding of the Hofer-Moest process with unprecedented chemoselectivity.

Defining the Macromolecules of Tomorrow through Synergistic Sustainable Polymer Research

Transforming how plastics are made, unmade, and remade through innovative research and diverse partnerships that together foster environmental stewardship is critically important to a sustainable future. Designing, preparing, and implementing polymers derived from renewable resources for a wide range of advanced applications that promote future economic development, energy efficiency, and environmental sustainability are all central to these efforts. In this Chemical Reviews contribution, we take a comprehensive, integrated approach to summarize important and impactful contributions to this broad research arena. The Review highlights signature accomplishments across a broad research portfolio and is organized into four wide-ranging research themes that address the topic in a comprehensive manner: Feedstocks, Polymerization Processes and Techniques, Intended Use, and End of Use. We emphasize those successes that benefitted from collaborative engagements across disciplinary lines.

ORGANOMETALLIC GAS-PHASE ION CHEMISTRY AND CATALYSIS: INSIGHTS INTO THE USE OF METAL CATALYSTS TO PROMOTE SELECTIVITY IN THE REACTIONS OF CARBOXYLIC ACIDS AND THEIR DERIVATIVES

Carboxylic acids are valuable organic substrates as they are widely available, easy to handle, and exhibit structural and functional variety. While they are used in many standard synthetic protocols, over the past two decades numerous studies have explored new modes of metal-mediated reactivity of carboxylic acids and their derivatives. Mass spectrometry-based studies can provide fundamental mechanistic insights into these new modes of reactivity. Here gas-phase models for the following catalytic transformations of carboxylic acids and their derivatives are reviewed: protodecarboxylation; dehydration; decarbonylation; reaction as coordinated bases in C-H bond activation; remote functionalization and decarboxylative C-C bond coupling. In each case the catalytic problem is defined, insights from gas-phase studies are highlighted, comparisons with condensed-phase systems are made and perspectives are reached. Finally, the potential role for mechanistic studies that integrate both gas- and condensed-phase studies is highlighted by recent studies on the discovery of new catalysts for the selective decomposition of formic acid and the invention of the new extrusion-insertion class of reactions for the synthesis of amides, thioamides, and amidines. © 2020 John Wiley & Sons Ltd. Mass Spec Rev.

Synthesis of Alpha Olefins: Catalytic Decarbonylation of Carboxylic Acids and Vegetable Oil Deodorizer Distillate (VODD)

Decarbonylation of carboxylic acids provides an effective protocol for producing alpha olefins; however, previous literature has focused on the palladium-bisphosphine catalysts and has only sporadically studied the palladium-monophosphine catalyst. To investigate the catalytic activity of the palladium-monophosphine catalyst on decarbonylation of carboxylic acids, new monophosphine ligands were synthesized (NP-1, NP-2, CP-1 and CP-2). By employing (1–3 mol%) palladium-naphthylphosphine catalysts, various carboxylic acids were converted into corresponding alpha alkenes with good yields and selectivity within a short period of time. Vegetable oil deodorizer distillate (VODD), which is a by-product from the vegetable oil refinery process, was found to be rich in free fatty acids and there is great interest in turning vegetable oil deodorizer distillate into value-added compounds. It is noteworthy that our catalytic system could be applied to convert vegetable oil deodorizer distillate (VODD) into diesel-like hydrocarbons in a good yield.

A facile method for Rh-catalyzed decarbonylative ortho-C–H alkylation of (hetero)arenes with alkyl carboxylic acids

A facile and effective method for Rh-catalyzed direct ortho-alkylation of C–H bonds in (hetero)arenes with commercially available carboxylic acids has been developed. This strategy was initiated by in situ conversion of carboxylic acids to anhydrides which, without isolation, underwent Rh-catalyzed direct decarbonylative cross-coupling of aryl carboxamides containing 8-aminoquinoline. The reaction proceeds with high regioselectivity and exhibits a broad substrate scope as well as functional group tolerance.

A facile and effective method for Rh-catalyzed direct ortho-alkylation of C–H bonds in (hetero)arenes with commercially available carboxylic acids has been developed.

Benefit of a hemilabile ligand in deoxygenation of fatty acids to 1-alkenes

One of the most important tasks for chemistry in our time is to contribute to sustainable chemical production. A green industrial process for linear α-olefins, the arguably most important class of petrochemical intermediates, from renewable resources would be a major contribution to this end. Plant oils are attractive renewable feedstocks for this purpose because their triglycerides can be hydrolyzed to fatty acids that contain valuable long-chain hydrocarbons (C16-C22). These hydrocarbons may, in turn, be converted to α-olefins by the deoxygenation of the fatty acids. For the most selective of these deoxygenation reactions, transition-metal catalyzed decarbonylative dehydration, the density functional theory (DFT) calculations have just started to offer valuable mechanistic insight, and the use of this insight in rational catalyst design has been facilitated by the arrival of the first well-defined precatalyst for this reaction, Pd(cinnamyl)Cl(DPEphos) (1). Here, we present DFT calculations showing how, in 1, the hemilability of DPEphos, a classical P-O-P diphosphine, contributes to a low overall barrier and high α-selectivity. DPEphos facilitates decarbonylation by first switching from bidentate to monodentate binding to create a coordination site for CO. The recoordination of the dangling phosphine displaces the Pd-bound CO, a co-product that must leave the reactor for the reaction to proceed, and the escaping CO is here modelled using a low pressure in the calculation of its thermochemical corrections. Finally, the role of the hemilabile ligand suggests that further improvements in the decarbonylative dehydration of fatty acids to α-olefins might be achieved by exploring new, potentially asymmetric, hemilabile ligands.

Na2CO3-promoted thioesterification via N–C bond cleavage of amides to construct thioester derivatives

A mild, efficient, and transition-metal-free catalytic strategy is developed to construct thioesters via selective N–C bond cleavage of Boc2-activated primary amides. This strategy is successfully carried out with stoichiometric Na2CO3 as the base and provides the corresponding products in moderate to excellent yields.

Straightforward formation of carbocations from tertiary carboxylic acids via CO release at room temperature

We report an unprecedented mode of reactivity of carboxylic acids. A series of tertiary carboxylic acids, containing at least one phenyl α-substituent, undergo loss of carbon monoxide at room temperature (295 K), by a one pot reaction with 0.5-1 molar equivalents of WCl₆ in dichloromethane. A plausible mechanism for the Ph₃CCO₂H/WCl₆ reaction, leading to [CPh₃][WOCl₅] and Ph₃CCl, is proposed on the basis of DFT calculations. The analogous reactions involving CEt(Ph)₂CO₂H, CMe(Ph)₂CO₂H and CMe₂(Ph)CO₂H selectively afforded stable hydrocarbons (alkene or indene, depending on the case), apparently resulting from the rearrangement of elusive tertiary carbocations.

ROS-mediated carbon monoxide and drug release from drug-conjugated carboxyboranes

Dual nature of amine carboxyboranes for combined CO and drug delivery is facilitated by ROS.

Ligand-induced decarbonylation in diphosphine-ligated palladium acetates [CH3CO2Pd((PR2)2CH2)]+ (R = Me and Ph)

Isotope labelling, IR spectroscopy and DFT calculations reveal a novel ligand-induced decarbonylation reaction.

Dual-catalytic decarbonylation of fatty acid methyl esters to form olefins

The homogeneous dehydrative decarbonylation of fatty acid methyl esters (FAMEs) to form olefins is reported.

Amines as effective ligands in iridium-catalyzed decarbonylative dehydration of biosourced substrates

Linear α-olefins (LAOs) and linear internal olefins (LIOs) are essential intermediates in the synthesis of surfactants, lubricants, and polymers.

Transition-metal-catalyzed decarbonylation of carboxylic acids to olefins: exploiting acyl C–O activation for the production of high value products

In this article, we review the recent developments in the transition-metal-catalyzed decarbonylation of carboxylic acids to produce olefins by the formal acyl C–O activation mechanism and discuss future challenges in this field.

Selective production of linear α-olefins via catalytic deoxygenation of fatty acids and derivatives

Various homogeneous, heterogeneous, and enzyme catalysis strategies for the selective synthesis of linear α-olefins from fatty acids and their derivatives are reviewed.