Tandem one-pot CO₂ reduction by PMHS and silyloxycarbonylation of aryl/vinyl halides to access carboxylic acids

Abstract

The synthesis of aryl/vinyl carboxylic acids from Csp2-bound halides (Cl, Br, I) in a carbonylative path by using silyl formate (from CO2 and hydrosilane) as an instant CO-surrogate.

Carbo-Carboxylation of Alkenes via Intramolecular Heck Carbonylation Utilizing CO2 and Hydrosilane

“…28,29,31,33−35 Our group has been committed to the carboxylation of organic compounds employing the in situ generated silyl formate from CO 2 and PMHS. 34,35 The silyloxycarbonylation path is confirmed during these reactions in which the silyl formate provides the source of CO and nucleophilic silanol. Within our recent efforts, we have developed palladium-catalyzed intramolecular Heck carbonylation reactions of diverse alkene-tethered aryl halides utilizing CO 2 and PMHS (Scheme 1d), which successfully construct a series of 2,3-dihydrobenzofuran-3ylacetic acids and 2,3-dihydro-1H-indene-1-acetic acids.…”

“…As an attractive and sustainable C 1 synthon, CO 2 has been not only used in various direct carboxylation reactions − but also participates in a series of carbonylation reactions as a promising CO surrogate to ultimately afford aldehydes, alcohols, carboxylic acids and carboxylic acid derivatives as products in the presence of suitable reductants. − Very recently, Yu’s group reported the application of nickel and chiral N,P-ligand in the asymmetric intramolecular reductive carbo-carboxylation of alkenes with CO 2 and Zn powder for the synthesis of oxindole-3-acetic acid derivatives (Scheme c, top) . Similarly, López and Bandini’s group developed nickel-catalyzed enantioselective CO 2 fixation enabled by a chiral N,N-ligand via a Heck-coupling/carboxylation cascade with Zn powder as a reducing agent and with trimethylsilyl chloride and tetrabutylammonium iodide as additives, producing a series of 2,3-dihydrobenzofuran-3-ylacetic acids as products in moderate yields (Scheme c, bottom). , These two reactions are examples of a direct carboxylation strategy and are similar to the form of the intramolecular carbo-carbonylation reactions.…”

“…Undoubtedly, hydrogen is the cleanest and most atom-economical reducing reagent. However, the reactions using hydrogen as a reductant usually require relatively harsh reaction conditions of high temperature and/or high pressure and may produce byproducts of substrates being reduced or products being reduced. ,, In contrast, PMHS is a kind of relatively cheap and easily available hydrosilane that can function as an effective reducing reagent converting CO 2 into silyl formate under extremely mild conditions. , Moreover, silyl formate has been demonstrated as an ideal carbonyl source for the construction of carbonyl-containing compounds in the related carbonylation processes. ,,,− Our group has been committed to the carboxylation of organic compounds employing the in situ generated silyl formate from CO 2 and PMHS. , The silyloxycarbonylation path is confirmed during these reactions in which the silyl formate provides the source of CO and nucleophilic silanol. Within our recent efforts, we have developed palladium-catalyzed intramolecular Heck carbonylation reactions of diverse alkene-tethered aryl halides utilizing CO 2 and PMHS (Scheme d), which successfully construct a series of 2,3-dihydrobenzofuran-3-ylacetic acids and 2,3-dihydro-1H-indene-1-acetic acids.…”

Carboxylation of Alkenyl Boronic Acids and Alkenyl Boronic Acid Pinacol Esters with CO2 Catalyzed by Cuprous Halide

“…1 H NMR (400 MHz, [D 6 ]DMSO) δ = 12.86 (s, 1H), 7.46–7.28 (m, 5H), 6.24 (s, 1H), 5.96 (s, 1H). 13 C NMR (101 MHz, [D 6 ]DMSO) δ = 168.22, 141.97, 137.18, 128.57, 128.47, 128.42, 126.53 …”

Sr2CoTaO6 Double Perovskite Oxide as a Novel Visible-Light-Absorbing Bifunctional Photocatalyst for Photocatalytic Oxygen and Hydrogen Evolution Reactions

“…Inexhaustible solar energy is considered as a promising renewable energy resource and conversion of solar energy into chemical energy as nature does is a viable means to storage, transportation, and implementation of solar energy. The development of photocatalytic water splitting systems is the primary reaction to produce solar fuels, but the development of efficient, stable, and cost-effect photocatalysts that function under visible light irradiation still remains elusive. − During the past few decades, enormous efforts have been made in developing efficient and stable earth-abundant element-based semiconductor photocatalysts for photocatalytic water splitting. − Particularly, perovskite oxide-based semiconductor photocatalysts with the chemical formula of ABO 3 , such as NaTaO 3 , Sr 2 M 2 O 7 (M = Ta and Nb), and SrTiO 3 , , have been intensively studied. In particular, it was found that selective photodeposition of dual redox cocatalysts Rh/Cr 2 O 3 and CoOOH on Al-doped SrTiO 3 can achieve overall water splitting with apparent quantum efficiency reaching nearly 100% at 360 nm UV light irradiation .…”