Evolution of carbonylation catalysis: no need for carbon monoxide

Progress in organometallic catalysis began with the discovery of the Roelen reaction (hydroformylation with carbon monoxide and hydrogen) in 1938 and the Reppe reaction (hydrocarboxylation with carbon monoxide and water) in 1939. Since then, carbonylation chemistry by using carbon monoxide has occupied a central position in organometallic chemistry, as it relates to organic synthesis. There is, however, the problem of using gaseous carbon monoxide (a toxic greenhouse gas) in this chemistry. Recently, some strategies that address this issue have appeared. This minireview describes carbonylation reactions that can be conducted without the direct use of carbon monoxide. These carbonylation reactions provide reliable and accessible tools for synthetic organic chemists.     

Recent progress on catalytic Heck carbonylations using carbon monoxide surrogates

Ongoing efforts toward the development of carbon monoxide (CO) surrogates have changed the way in which carbonylative transformations are conducted. For synthesizing carboxylic acid derivatives, Heck carbonylation using CO surrogates in slight excess has become a more efficient and practical method than the conventional one using large excess of CO gas. To supply CO for the reaction, both in-situ and ex-situ methods has been considered. Herein, we summarize recent progress in catalytic Heck carbonylation using CO surrogates, including discussion of the mechanism for CO generation from recently developed CO surrogates.     

Homogeneous catalysis by ruthenium carbonyl clusters

The historical background of and the incentive for using ruthenium carbonyl clusters as homogeneous catalysts are outlined. Keeping in view the possible solutions the uncertainties arising from declusterification and metal colloid formation are discussed. All ruthenium cluster-catalysed reactions are broadly classified as reactions with or without carbon monoxide as one of the reactants and the basic differences between such reactions are highlighted. Some of the factors of special relevance to cluster-catalysed reaction systems are mentioned. The reactions involving carbon monoxide are then discussed. These include water-gas-shift reaction, carbon monoxide hydrogenation, hydroformylation, reductive carbonylation of nitrobenzene and other carbonylation reactions. Hydrogenation, transfer hydrogenation, isomerisation and a few other reactions are then discussed. For all these reactions, special emphasis is laid on well-characterised cluster complexes that have been proposed as catalytic intermediates. Finally an attempt has been made to identify the path that future research in cluster catalysis is likely to follow.     

一氧化碳参与不饱和烃类化合物羰基化反应的研究进展

不饱和烃类化合物的羰基化反应是指在过渡金属催化剂存在条件下, 将一氧化碳(CO)分子以羰基的形式插入到烯烃(或者炔烃)与不同的亲核试剂中, 合成更高附加值化学品的转化过程. 本文综合评述了羰基化反应合成高附加值化学品的重要性, 介绍了几种不同类型的羰基化反应(氢甲酰化反应、 氢酯化反应、 氢酰胺化反应和氢羧基化反应)在发展新型催化剂体系及高效合成目标产物方面的研究进展, 并对羰基化反应存在的问题及未来发展方向和趋势进行了展望.     

Dimethylformamide as a carbon monoxide source in fast palladium-catalyzed aminocarbonylations of aryl bromides

Dimethylformamide (DMF) acts as an efficient source of carbon monoxide and dimethylamine in the palladium-catalyzed aminocarbonylation (Heck carbonylation) of p-tolyl bromide to provide the dimethylamide. Addition of amines to the reaction mixture in excess delivers the corresponding aryl amides in good yields. The amines employed, benzylamine, morpholine, and aniline, all constitute good reaction partners. The reaction proceeds smoothly with bromobenzene and more electron-rich aryl bromides, but electron-deficient aryl bromides fail to undergo aminocarbonylation. The reactions are conducted at 180-190 degrees C for 15-20 min with microwave heating in a reaction mixture containing imidazole and potassium tert-butoxide: the latter is required to promote decomposition of the DMF solvent at a suitable rate. The beneficial effects of controlled microwave irradiation as an energy source for the rapid heating of the carbonylation reaction mixture are demonstrated. The carbonylation procedure reported herein, which relies on the in situ generation of carbon monoxide, serves as a convenient alternative to other carbonylation methods and is particularly applicable to small-scale reactions where short reaction times are desired and the direct use of carbon monoxide gas is impractical.     

Synthesis of Acylphosphonates by a Palladium‐Catalyzed Phosphonocarbonylation Reaction of Aryl Iodides with Phosphites

Acylphosphonates are conveniently synthesized from aryl iodides by a palladium‐catalyzed reaction with dialkyl phosphites under an atmospheric pressure of carbon monoxide. The reaction demonstrates the first example of the use of phosphorus nucleophiles in related metal‐catalyzed carbonylation reactions.     

硒催化反应最新研究进展

价廉易得的非金属硒作催化剂不但具有良好的催化活化CO的性能及反应过程相转移催化特性, 而且能循环使用. 用Se/CO催化体系替代贵金属催化羰基化法及剧毒的光气法进行羰基化反应及用Se/CO/H2O催化体系进行高选择性的还原反应, 具有反应条件温和、原子经济性高、成本低、环境友好、路线简短、后处理方便等优点, 因而引起人们的广泛关注. 概述了近几年来硒催化羰基化反应和硒催化选择性还原反应的最新研究进展, 并对硒催化反应的发展趋势进行了展望.     

An effective Pd-catalyzed hydroxycarbonylation of olefins with CO and HCOOH

A new protocol for Pd-catalyzed regioselective hydroxy-carbonylation of olefins with formic acid under low pressure of carbon monoxide has been developed. The same catalytic system provides good selectivity to 2-phenylpropionic acid in carbonylation of styrene and to linear acids in carbonylation of terminal alkenes. The reaction is highly susceptible to catalyst precursor and solvent nature.     

2-硒代咪唑类化合物催化CO与胺的羰基化反应

首次研究了2-硒代咪唑类化合物催化的一氧化碳对胺的羰基化生成对称脲或噁唑啉-2-酮的反应,目标产物收率中等到良好.与传统的单质硒催化的羰基化反应相比,新催化体系有效避免了有恶臭气味的含硒化合物的产生.     

New approaches in radical carbonylation chemistry: fluorous applications and designed tandem processes by species-hybridization with anions and transition metal species

New approaches in radical carbonylation chemistry are described. We have successfully integrated tin mediated radical carbonylation chemistry into modern fluorous applications and separation techniques. We revealed that radical carbonylation reactions can be performed using fluorous tin mediators, such as fluorous tin hydride and fluorous allyltin reagents. Fine tuning of the reaction conditions resulted in a good efficiency equivalent to conventional tin mediators. The tedious procedure of removing organotin byproducts can be circumvented through the use of fluorous/organic liquid-liquid extraction or fluorous liquid-solid phase extraction with fluorous reverse phase silica (FRPS). Also described are newly developed tandem carbonylation reactions that are based on species hybridization approaches. Using a radical/anionic hybrid system based on zinc-induced one-electron reduction, we achieved a three-component coupling reaction consisting of 4-alkenyl iodides, carbon monoxide, and electron-deficient alkenes. We observed two types of annulations processes, namely [4 + 1](radical)/[3 + 2](anionic) and [5 + 1](radical)/[3 + 2](anionic), which lead to the production of bicyclo[3.3.0]octanols and bicyclo[3.2.1]octanols, respectively. We found a radical/palladium hybrid system to be useful in the construction of new cyclic systems that incorporate two or three molecules of carbon monoxide.     

Palladium‐Catalyzed Oxidative Carbocyclization–Carbonylation of Allenynes and Enallenes

A highly efficient oxidative carbocyclization–carbonylation reaction cascade of allenynes and enallenes has been developed using a Pd^II salt in low catalytic amounts under ambient temperature and pressure (1 atm of carbon monoxide). The use of DMSO as an additive was found to be important for an efficient reaction. A wide range of alcohols as trapping reagents were used to give the corresponding esters in good yields.     

Palladium-catalyzed esterification of aryl halides using aryl formates without the use of external carbon monoxide

Aryl formates are efficient carbon monoxide sources in palladium-catalyzed esterification of aryl halides. The carbonylation readily proceeds at ambient pressure without the use of external carbon monoxide to afford the corresponding esters in high yields.     

Palladium-catalyzed double carbonylation using near stoichiometric carbon monoxide: expedient access to substituted 13C2-labeled phenethylamines

A novel and general approach for (13)C(2)- and (2)H-labeled phenethylamine derivatives has been developed, based on a highly convergent single-step assembly of the carbon skeleton. The efficient incorporation of two carbon-13 isotopes into phenethylamines was accomplished using a palladium-catalyzed double carbonylation of aryl iodides with near stoichiometric carbon monoxide.     

Polyethylene-bound complexes in carbon monoxide catalytic reactions

Catalytic reactions of carbon monoxide are investigated in presence of polyethylene-bound palladium and rhodium complexes and it was shown that such catalysts with temperature-dependent solubility are applicable for carbonylation of organic halides and hydroformylation of alkenes due to high activity and recoverability.     

Palladium‐Catalyzed Oxidative Cascade Carbonylative Spirolactonization of Enallenols

A highly selective palladium‐catalyzed oxidative carbonylation/carbocyclization/alkoxycarbonylation of enallenols to afford spirolactones bearing an all‐carbon quaternary center was developed. This transformation involves the overall formation of three C−C bonds and one C−O bond through a cascade insertion of carbon monoxide (CO), an olefin, and CO. Preliminary experiments on chiral anion‐induced enantioselective carbonylation/carbocyclization of enallenols afforded spirolactones with moderate enantioselectivity.     

Photoinitiated free radical carbonylation enhanced by photosensitizers

[reaction: see text] The enhancing effect of several photosensitizers in photoinitiated radical carbonylation is demonstrated and applied to accelerate the synthesis of compounds labeled with short-lived 11C. With the sensitizers, the synthesis of [carbonyl-11C]esters and acids from alkyl iodides, [11C]carbon monoxide, alcohols, and water provided up to 75-85% decay-corrected radiochemical yields in 6-min reactions under mild conditions. Acetone was used as a sensitizer in preparing 13C-substituted 1,10-decanedicarboxylic acid from (13C)carbon monoxide.     

Transition metal-catalyzed cyclocarbonylation in organic synthesis

Cyclocarbonylation reactions proceed mainly by the coupling reactions of carbonylation components with cyclization components having an unsaturated π-electron bond, in the presence of transition metal compounds. The representative reactions are cyclocarbonylation of alkynes by carbon monoxide such as Pauson–Khand reactions, hetero Pauson–Khand reactions, cyclocarbonylation of alkynyl alcohols, cyclocarbonylation of alkynyl amines, cyclocarbonylative alkyne–alkyne coupling reactions, and reductive cyclocarbonylation of alkynes. The other reactions are cyclocarbonylation of alkenes by carbon monoxide such as alkene–alkene coupling reactions, cyclocarbonylation with aldehydes, ketones, amines or imines, cyclocarbonylation of alkenyl alcohols. Carbonylation via cyclometalation, carbonylative ring expansion reactions, cyclocarbonylation by aldehydes, carboxylic acids or carboxylic acid esters are also cyclocarbonylation reactions. These reactions are conveniently used for organic syntheses, especially, for the syntheses of pharmaceutical intermediates.     

Ultrafast chemistry: cobalt carbonyl-mediated synthesis of diaryl ketones under microwave irradiation

By combining the advantages of metal activation, in situ carbon monoxide delivery, and microwave heating, benzophenones were efficiently synthesized in 6-10 s. These ultrafast carbonylation reactions occur under air by flash heating of aryl iodides in the presence of dicobalt octacarbonyl. [reaction: see text]     

Investigation of the effect of carbon monoxide on the oxidative carbonylation of methanol to dimethyl carbonate over CuX and CuZSM-5 zeolites

Direct synthesis of dimethyl carbonate offers prospects for a “green chemistry” replacement to eliminate use of phosgene for polymer production and other processes. The carbonylation of methanol to produce dimethyl carbonate over Cu⁺X and Cu⁺ZSM-5 zeolites prepared by solid-state ion exchange has been investigated, focusing on the interaction of carbon monoxide with the Cu⁺ zeolites. The methanol carbonylation mechanism reported previously has been extended to account for carbon monoxide adsorption at high pressure. The comparison of the results obtained from Cu⁺X and Cu⁺ZSM-5 show that strong CO adsorption on the catalyst is not related to increased rate of dimethyl carbonate production. The rate limiting step for DMC production is best described as the Eley-Rideal reaction of gas-phase CO with surface methoxide.     

硒催化羰基化合成苯并噻唑-2-氨基甲酸酯

以非金属Se为催化剂,以CO替代剧毒光气及其复杂衍生物作羰基化试剂,以O2为氧化剂,经2-氨基苯并噻唑与醇发生"一锅法"的硒催化氧化羰基化反应,开辟了一条经济、绿色、简便、高效的合成苯并噻唑-2-氨基甲酸酯类化合物的新途径.研究了反应温度、压力、醇的用量及碱的种类等因素对生成苯并噻唑-2-氨基甲酸酯的影响,获得了实施该...