Ru催化的C-H键的活化反应

概述了Ru催化的碳氢键的活化反应，包括C-H/烯烃，C-H/炔径和C-H/CO/烯烃 偶联反应，加氢酰化反应，硅化反应。     

Biocatalysis in ionic liquids: batchwise and continuous flow processes using supercritical carbon dioxide as the mobile phase

A new and environmentally benign protocol for enzymatic reactions in ionic liquids is described using supercritical CO2 as the mobile phase; the products are obtained in solvent-free form and the enzyme/ionic liquid mixture can be recycled in batchwise or continuous flow operations.     

An efficient catalytic protocol for the Pauson-Khand reaction

New experimental conditions have been developed for an efficient catalytic Pauson-Khand reaction. These are based on the use of a mixture of molecular sieves and tert-butanol as inducers of the process. This mixture, with the appearance of a paste, is able to adsorb CO, thus improving the conversion and making it possible to effect the reactions in the absence of a CO atmosphere. The protocol is applied to known and unknown substrates and compared to previously described conditions, showing good results with intra- and intermolecular examples.     

Photoinduced Five-Component Radical Relay Aminocarbonylation of Alkenes

Radical single carbonylation reactions with CO constitute a direct and robust strategy toward various carbonyl compounds from readily available chemicals, and have been extensively studied over the past decades. However, realizing highly selective catalytic systems for controlled radical double carbonylation reactions has remained a substantial challenge, particularly for the more advanced multicomponent variants, despite their great potential value. Herein, we report a visible-light-driven radical relay five-component radical double aminocarbonylation reaction of unactivated alkenes using CO under metal-free conditions. This protocol provides direct access to valuable γ-trifluoromethyl α-ketoamides with good yields and high chemoselectivity. Crucial was the identification of distinct dual roles of amine coupling partners, sequentially acting as electron donors for the formation of photoactive electron donor-acceptor (EDA) complexes with radical precursors and then as a CO acceptor via nitrogen radical cations to form carbamoyl radicals. Cross-coupling of carbamoyl radicals with the acyl radicals that are formed in an alkene-based relay process affords double aminocarbonylation products.     

Morita-Baylis-Hillman acetates of acetylenic aldehydes: versatile synthons for substituted pyrroles via a metal-free tandem reaction

A mild and metal-free access to 1,2,4-tri or 1,2,4,5-tetrasubstituted pyrroles has been developed by the reaction of Morita-Baylis-Hillman acetates of acetylenic aldehydes with amines and sulfonamides. This new protocol is based on K(2)CO(3)-promoted tandem allylic substitution/cycloisomerization reactions.     

Aqueous-phase, thermal Pauson-Khand reactions in the presence of surfactants

Efficient stoichiometric Pauson-Khand reactions were realized in water as the only solvent, and in the presence of surfactants as additives. Use of the cationic surfactant CTAB provided good yields of cyclopentenones from the thermal reactions of pre-formed dicobalthexacarbonyl complexes of enynes and alkynes. The water-CTAB medium was found to be less effective with Co₄(CO)₁₂ as the promoter of the reaction. Incidentally, these results have provided a strictly water-based PKR protocol under very mild and convenient conditions.     

水相中苯并噻唑类衍生物的微波辐射合成

在水相中建立了一种简单实用,廉价的2-碘芳胺与芳醛和硫氰酸钾反应生成苯并噻唑衍生物的微波辅助铜催化体系。该体系只需以碘化亚铜和1,10-菲罗啉为催化剂,以碳酸铯为碱的100 ℃水中反应30 min,就能得到大量苯并噻唑衍生物,最高产率达94%。     

Facile deallylation protocols for the preparation of N-unsubstituted triazoles and tetrazoles

Two facile deallylation protocols have been developed for the preparation of N-unsubstituted triazoles and tetrazoles. The first protocol is a direct deallylation using a combination of a catalytic amount of nickel complex, NiCl2(dppe), and a stoichiometric amount of Grignard reagent, tBuMgCl. The second protocol is a stepwise deallylation through consecutive reactions of isomerization and ozonolysis. The isomerization from N-allylazoles to N-vinylazoles is catalyzed by a ruthenium complex, HRuCl(CO)(PPh3)3, and the following ozonolysis of the derived N-vinyl intermediates affords N-unsubstituted azoles. These protocols can be used complementarily depending on the type of functional groups in the parent allylated azoles.     

Ex situ generation of stoichiometric and substoichiometric 12CO and 13CO and its efficient incorporation in palladium catalyzed aminocarbonylations

A new technique for the ex situ generation of carbon monoxide (CO) and its efficient incorporation in palladium catalyzed carbonylation reactions was achieved using a simple sealed two-chamber system. The ex situ generation of CO was derived by a palladium catalyzed decarbonylation of tertiary acid chlorides using a catalyst originating from Pd(dba)(2) and P(tBu)(3). Preliminary studies using pivaloyl chloride as the CO-precursor provided an alternative approach for the aminocarbonylation of 2-pyridyl tosylate derivatives using only 1.5 equiv of CO. Further design of the acid chloride CO-precursor led to the development of a new solid, stable, and easy to handle source of CO for chemical transformations. The synthesis of this CO-precursor also provided an entry point for the late installment of an isotopically carbon-labeled acid chloride for the subsequent release of gaseous [(13)C]CO. In combination with studies aimed toward application of CO as the limiting reagent, this method provided highly efficient palladium catalyzed aminocarbonylations with CO-incorporations up to 96%. The ex situ generated CO and the two-chamber system were tested in the synthesis of several compounds of pharmaceutical interest and all of them were labeled as their [(13)C]carbonyl counterparts in good to excellent yields based on limiting CO. Finally, palladium catalyzed decarbonylation at room temperature also allowed for a successful double carbonylation. This new protocol provides a facile and clean source of gaseous CO, which is safely handled and stored. Furthermore, since the CO is generated ex situ, excellent functional group tolerance is secured in the carbonylation chamber. Finally, CO is only generated and released in minute amounts, hence, eliminating the need for specialized equipment such as CO-detectors and equipment for running high pressure reactions.     

Selective Ru(0)-catalyzed deuteration of electron-rich and electron-poor nitrogen-containing heterocycles

A highly selective Ru(3)(CO)(12)-catalyzed deuteration method using t-BuOD as deuterium source is reported. Electron-rich and electron-poor N-heteroarenes such as indoles, azaindoles, deazapurines, benzimidazole, quinolines, isoquinolines, and pyridines were efficiently deuterated at specific positions with high selectivity; in most cases, deuterium incorporation was close to the theoretically possible values. To further increase deuteration degrees, several cycles of the reaction protocol can be carried out which gave superior deuteration degrees employing a much lower excess of deuterating agent compared to established protocols. It was proved that the same protocol can in principle be applied to tritiation reactions important for radioactive labeling of bioactive molecules.     

In Situ FTIR and NMR Spectroscopic Investigations on Ruthenium‐Based Catalysts for Alkene Hydroformylation

Homogeneous ruthenium complexes modified by imidazole‐substituted monophosphines as catalysts for various highly efficient hydroformylation reactions were characterized by in situ IR spectroscopy under reaction conditions and NMR spectroscopy. A proper protocol for the preformation reaction from [Ru₃(CO)₁₂] is decisive to prevent the formation of inactive ligand‐modified polynuclear complexes. During catalysis, ligand‐modified mononuclear ruthenium(0) carbonyls were detected as resting states. Changes in the ligand structure have a crucial impact on the coordination behavior of the ligand and consequently on the catalytic performance. The substitution of CO by a nitrogen atom of the imidazolyl moiety in the ligand is not a general feature, but it takes place when structural prerequisites of the ligand are fulfilled.     

Copper-catalyzed synthesis of benzimidazoles via cascade reactions of o-haloacetanilide derivatives with amidine hydrochlorides

We have developed an efficient method for the synthesis of benzimidazoles via cascade reactions of o-haloacetoanilide derivatives with amidine hydrochlorides. The protocol uses 10 mol % CuBr as the catalyst, Cs2CO3 as the base, and DMSO as the solvent, and no ligand is required. The procedure proceeds via the sequential coupling of o-haloacetoanilide derivatives with amidines, hydrolysis of the intermediates (amides), and intramolecular cyclization with the loss of NH3 to give 2-substituted 1H-benzimidazoles.     

Easy-to-execute carbonylations: microwave synthesis of acyl sulfonamides using Mo(CO)(6) as a solid carbon monoxide source

The development of a robust palladium-catalyzed amidocarbonylation protocol for the preparation of aromatic acyl sulfonamides utilizing high-density microwave heating is described. This synthetic approach employs Mo(CO)(6) as a convenient CO-releasing reagent and allows for the direct preparation of acyl sulfonamides from both aryl iodides and aryl bromides. The reactions can be performed under air, employing only 15 min of microwave irradiation, to produce acyl sulfonamide derivatives in good to excellent yields. To illustrate the usefulness of this method, we reported the synthesis of a novel hepatitis C virus NS3 protease inhibitor.     

Carbonylation of Difluoroalkyl Bromides Catalyzed by Palladium

Although important progress has been made in the fluoroalkylation reactions, the transition‐metal‐catalyzed carbonylative fluoroalkylation reaction remains challenging so far. Herein, we report the first example of a Pd‐catalyzed carbonylation of difluoroalkyl bromides with (hetero)arylboronic acids under one atmosphere pressure of CO. The reaction can also be extended to the aryl potassium trifluoroborate salts. The advantages of this protocol are synthetic simplicity, broad substrate scope, and excellent functional group compatibility. The resulting difluoroalkyl ketones can serve as versatile building blocks for the synthesis of various useful fluorinated compounds.     

二氧化碳作为羧化试剂用于羧酸及其衍生物的合成(英文)

二氧化碳是储量丰富、廉价易得且可再生的C1资源,将其催化转化成高附加值精细化学品的研究已经引起了人们的广泛关注.目前,虽然二氧化碳用作初始原料的反应已经工业化的很少,但过去几十年中仍有二十多个具有实际应用前景的二氧化碳参与的新反应被发现,其中以二氧化碳作为羧化试剂合成各种羧酸及其衍生物的反应为突出代表.本文综述了过渡金属催化合成羧酸及其衍生物的二氧化碳与多种碳亲核试剂、碳氢键以及碳碳多重键化合物的反应,并总结了无过渡金属参与或有机小分子催化条件下将二氧化碳转化成羧酸及其衍生物的反应.     

二氧化碳在化学合成上的研究进展

二氧化碳合成化学在发展对环境友好的新合成工艺和利用ＣＯ２制备附加价值较高的化工产品等方面的研究取得了重要进展,它有助于减少ＣＯ２对大气中的排放量。     

Regiochemistry in cobalt-mediated intermolecular Pauson-Khand reactions of unsymmetrical internal heteroaromatic alkynes with norbornene

The intermolecular Pauson-Khand (PK) reactions of sterically comparable (2-phenylethynyl)heteroaromatic compounds with norbornene, mediated by Co(2)(CO)(8) to give cyclopentenone products, were examined in this study. A synthetic protocol utilizing focused-microwave dielectric heating proved indispensable in the efficient synthesis of the PK cyclopentenone products. "π-Deficient" heteroaromatic substrates, e.g., 2-pyrones, and some "π-excessive" heteroaromatics such as 2- and 3-thiophene and 2-furan favor the β-position in the newly formed cyclopentenone ring. Other π-excessive heteroaromatics such as 2-pyrrole or 2-indole favor the α-position. A π-excessive 3-indole derivative gave a nearly equal mixture of regioisomers. The position of the nitrogen in pyridyl-containing alkyne substrates also affects the regiochemical outcome of the PK reaction. A 2-pyridyl alkyne, possessing a proximal nitrogen, influences the regioselectivity relative to a 4-pyridyl variant quite dramatically, favoring the β-position in the newly formed cyclopentenone ring. A 2-pyrimidylalkyne exhibits similar behavior to the 2-pyridylalkyne. Compounds that do not participate in PK reactions with norbornene include (2-phenylethynyl)imidazoles and the related benzimidazoles, which promote rapid decomposition of the in situ generated (μ(2)-alkyne)Co(2)(CO)(6) complexes. This stands in contrast with other nitrogen-containing heteroaromatics, e.g., pyrrole-, indole-, and pyrimidine-derived compounds, which effectively undergo PK reactions. Overall, the type of heteroaromatic group dramatically influences PK regioselectivity, which can in part be explained by rationalization of the current reaction mechanism, but not fully.     

二氧化碳直接加氢合成反应的热力学分析(英文)

二氧化碳直接加氢合成反应是二氧化碳活化和有效利用的重要途径之一。列举了１８个二氧化碳氢化反应,并对相应的反应热和平衡常数进行了计算。假定各反应物以反应的摩尔计量比参加反应、反应物的总量均为１ｍｏｌ,求出了各反应中ＣＯ２的平衡转化率。     

Palladium-catalyzed carbonylative synthesis of N-cyanobenzamides from aryl iodides/bromides and cyanamide

A novel and convenient protocol for the synthesis of N-cyanobenzamides starting from readily available aryl halides and cyanamide via palladium-catalyzed aminocarbonylation has been developed. The protocol utilizes Mo(CO)₆ as the CO source or CO(gas) and affords the desired N-cyanobenzamides in moderate to good yields.     

Synthesis and properties of fac-Re(dmbpy)(CO)3CHO (dmbpy = 4,4'-dimethyl-2,2'-bipyridine), a possible intermediate in reductions of CO2 catalyzed by fac-Re(dmbpy)(CO)3Cl

Synthesis of fac-Re(dmbpy)(CO)3CHO 2 and its reactions with CO2 in DMF and DMSO have been conducted; 2 transfers hydride to CO2 to give Re(dmbpy)(CO)4+ OCHO- 5 which is rapidly transformed to fac-Re(dmbpy)(CO)3(OCHO) 3 in DMF, thus supporting the viability of 2 in photocatalytic reactions of fac-Re(dmbpy)(CO)3Cl with CO2.