Successive copper(I)-catalyzed cross-couplings in one pot: A novel and efficient starting point for synthesis of carbapenems
TL;DR: An efficient approach for synthesizing a series of 2-sulfide carbapenems has been developed using two successive Cu(I)-catalyzed cross-couplings in a single pot.
About: This article is published in Organic Letters.The article was published on 2008-05-30. It has received 53 citations till now.
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1,326 citations
TL;DR: Recent efforts in metal-catalyzed C-S bond cross-coupling reactions are summarized, focusing especially on the coupling of thiols with aryl- and vinyl halides based on different metals.
Abstract: Sulfur-containing molecules such as thioethers are commonly found in chemical biology, organic synthesis, and materials chemistry. While many reliable methods have been developed for preparing these compounds, harsh reaction conditions are usually required in the traditional methods. The transition metals have been applied in this field, and the palladium-catalyzed coupling of thiols with aryl halides and pseudo halides is one of the most important methods in the synthesis of thioethers. Other metals have also been used for the same purpose. Here, we summarize recent efforts in metal-catalyzed C-S bond cross-coupling reactions, focusing especially on the coupling of thiols with aryl- and vinyl halides based on different metals.
351 citations
TL;DR: This review discusses the metal-catalyzed arylation of thiols and the use of disulfides as metal-thiolate precursors for the formation of C-S bonds.
Abstract: The presence of aryl sulfides in biologically active compounds has resulted in the development of new methods to form carbon-sulfur bonds. The synthesis of aryl sulfides via metal catalysis has significantly increased in recent years. Historically, thiolates and sulfides have been thought to plague catalyst activity in the presence of transition metals. Indeed, strong coordination of thiolates and thioethers to transition metals can often hinder catalytic activity; however, various catalysts are able to withstand catalyst deactivation and form aryl carbon-sulfur bonds in high-yielding transformations. This review discusses the metal-catalyzed arylation of thiols and the use of disulfides as metal-thiolate precursors for the formation of C-S bonds.
227 citations
Cites background from "Successive copper(I)-catalyzed cros..."
...Copper-Catalyzed Arylation of Thiols Over the last decade, copper has emerged as a viable catalyst for the arylation of thiols.[27,67-103] Palomo and co-workers demonstrated the ability of CuBr with phosphazene base to catalyze reaction between aryl iodides and thiols to afford biaryl sulfides Equation (12) [67]....
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TL;DR: The reaction described herein is the first example of a tandem catalytic process that incorporates a C S coupling, as well as the first examples of the palladium-catalyzed vinylation of a thiol, and was found to tolerate changes in the electronic nature of the boronic acid.
Abstract: Transition-metal-catalyzed cross-coupling reactions have become indispensable tools for the synthetic chemist. 2] The construction of carbon–heteroatom bonds is of particular interest. Consequently, a large number of general and efficient systems for the catalytic amination and etherification of aryl and vinyl halides have been described. 4] In contrast, research in the field of carbon–sulfur coupling reactions has lagged behind, largely because of sulfur’s long-standing reputation as a catalyst poison. Despite this difficulty, coupling reactions of thiols with aryl halides under the catalysis of Pd, Cu, Ni, Co, Fe, and In have been reported. Reactions of vinyl halides are comparatively rare: only a handful of publications describe the vinylation of thiols, 15] and the palladium-catalyzed intramolecular coupling is unknown. We anticipated that the use of Pd could facilitate access to a number of tandem coupling reactions in which an Svinylation reaction could be combined with orthogonal carbon–carbon bond formation in a single synthetic operation. Tandem/domino reactions are an area of intense research, as they enable streamlined synthetic sequences and a consequent reduction of waste. Herein, we disclose a tandem catalytic reaction of a gem-dihalovinyl thiophenol system in which an intramolecular S-vinylation is paired with an intermolecular C C bond-forming reaction (a Suzuki– Miyaura, Heck, or Sonogashira reaction) to yield 2-substituted benzothiophenes (Scheme 1). These heterocycles form the core of a number of medicinally important molecules, such as raloxifene and zileuton. However, catalytic routes to these targets have only recently been developed. To the best of our knowledge, the reaction described herein is the first example of a tandem catalytic process that incorporates a C S coupling, as well as the first example of the palladium-catalyzed vinylation of a thiol. We and others have previously reported the synthesis of indoles substituted at the 2-position by tandem coupling reactions of gem-dihalovinyl anilines. In these systems, an intramolecular amination or amidation was combined with an interor intramolecular Suzuki–Miyaura, Heck, or Sonogashira coupling, amidation, direct arylation, or carbonylation. Similar transformations involving C S coupling would provide rapid access to benzothiophenes and expand the range of available tandem coupling reactions. Our initial attempts were aimed at combining the carbon– sulfur bond-forming process with a Suzuki–Miyaura coupling (Table 1). We found that the conditions developed previously for the aniline system were less effective for the thiophenol substrate 1a : the desired product was isolated in only 48% yield (Table 1, entry 1). The screening of various bases (Table 1, entries 1–4, 8), precatalysts (entries 5–7), and ligand/ catalyst ratios (entries 9 and 10) revealed that the best results were obtained when the reaction was carried out with PdCl2, SPhos, and anhydrous K3PO4/Et3N in dioxane at 110 8C. Under these conditions, 2 a was formed in 89 % yield (Table 1, entry 10). Lowering of the catalyst loading to 1 mol % led to enhanced turnover with minimal impact on the yield (Table 1, entry 12). With these optimized conditions in hand, we investigated the effect of varying the boronic acid on the tandem process (Table 2). The reaction was found to tolerate changes in the electronic nature of the boronic acid. Electron-poor boronic acids displayed similar reactivity to that of electron-rich 3,4dimethoxyphenylboronic acid: the boronic acid used for optimization of the reaction (Table 2, entries 1–4). The coupling proceeded equally well when a sterically congested boronic acid was used (Table 2, entry 5). The use of heteroaromatic boronic acids gave the best results: the corresponding heterocyclic products were obtained in up to 99% yield Scheme 1. Retrosynthetic strategy.
171 citations
TL;DR: An efficient synthetic approach to variously substituted thiophenes has been developed through copper-catalyzed tandem S-alkenylation of potassium sulfide with 1,4-diiodo-1,3-dienes.
144 citations
References
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TL;DR: In this article, the authors highlight the recent developments in the copper-mediated (both stoichiometric and catalytic) reactions of aryl boronic acids as reaction partners in both O- and N-arylation.
Abstract: The copper-mediated C(aryl)N, C(aryl)O, and C(aryl)S bond formation is an important transformation and has been developed to include a wide range of substrates. This Review highlights the recent developments in the copper-mediated (both stoichiometric and catalytic) reactions of aryl boronic acids, aryl halides, iodonium salts, siloxanes, stannanes, plumbanes, bismuthates, and trifluoroborate salts as aryl donors. In particular, the recent introduction of boronic acids as reaction partners in both O- and N-arylation has been a significant discovery and will occupy centre-stage in this review. Clear improvements can be obtained by the correct choice of copper source, base, ligands, and other additives. Mechanistic investigations should provide insight into the catalytically active species, which would aid in the development of milder, more-efficient methods.
2,280 citations
TL;DR: A wide range of aryl reagents have been explored in the past five years as mentioned in this paper, of which the aryls halides are among the most promising procedures, covering the litera- ture published through May 2003.
Abstract: Copper-catalyzed C-N-, C-O- and C-S-coupling reac- tions are powerful tools in organic synthesis and have been exten- sively reinvestigated in the past five years. The understanding of solubilizing and accelerating effects exhibited by substrates and ligands initiated novel developments originally on N-arylation of amines, amides, and nitrogen heterocycles. Nevertheless practical methods for the syntheses of aryl ethers and aryl thioethers have been established as well. A wide range of arylating reagents was ex- plored, of which the aryl halides will be presented in this overview. Among a growing set of ligands and optimized reaction protocols, the most promising procedures are highlighted, covering the litera- ture published through May 2003.
671 citations
TL;DR: A general and efficient copper-catalyzed method for the amidation of vinyl bromides and iodides has been developed and the double bond geometry of the vinyl halides was retained under the reaction conditions.
360 citations
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