Silicon-based cross-coupling reaction: an environmentally benign version

Much attention has been paid to the cross-coupling reaction of organosilicon compounds due to their stability, non-toxicity, and natural abundance of silicon. In addition, the silicon-based cross-coupling has many advantages over other cross-coupling protocols. Successful examples of the silicon-based cross-coupling reaction are reviewed, focusing especially on the advances made in the last decade. Having had a number of highly effective palladium catalysts developed mainly for other cross-coupling reactions, the development of the silicon-based protocol owes heavily to the design of organosilicon reagents which effectively undergo transmetalation, a key elemental step of the silicon-based cross-coupling reaction. This tutorial review thus classifies various organosilicon reagents depending on substituents on silicon and surveys their cross-coupling reactions with various electrophiles.     

N-tosylhydrazones: versatile reagents for metal-catalyzed and metal-free cross-coupling reactions

Transition metal-catalyzed cross-coupling reactions have been established as one of the most powerful tools for the construction of C-C and C-X bonds. In this context, the development of novel metal-catalyzed cross-coupling processes that do not require stoichiometric organometallic reagents is particularly attractive. Recently, N-tosylhydrazones have emerged as a new type of versatile coupling partners for transition metal-catalyzed cross-coupling reactions as well as metal-free cross-coupling reactions, and have attracted increasing attention. This tutorial review summarizes recent important developments in this area with N-tosylhydrazones as versatile coupling partners.     

可见光参与的氧化偶联反应研究进展

实现资源和能源利用高效化、操作简单化、条件温和化、环境友好化以及产物高效选择性是有机合成的重要研究方向,而探索绿色温和条件下构建化学键的有效方法是有机合成领域的基本挑战之一。伴随着金属有机化学的发展,过渡金属催化的偶联反应已经成为构建碳-碳和碳-杂键的有效手段,而传统的交叉偶联一般是基于亲核试剂与亲电试剂之间的反应,需要进行预官能团化和再官能团化的步骤。近年来,在此基础上发展起来的氧化偶联反应利用合适的氧化剂实现两个亲核试剂直接构建化学键也得到了国内外有机化学家的广泛关注。氧化偶联反应的发展极大地提高了构建碳-碳键及碳-杂键的效率,尤其是利用交叉脱氢偶联实现直接的碳-氢键或杂-氢键的活化直接构建化学键,避免了传统偶联过程中的预官能团化步骤,为直接利用简单的原料实现高效、复杂的有机合成开辟了一条新的道路。越来越多的第一过渡金属催化的氧化偶联反应涉及到单电子转移的过程,这种自由基氧化偶联模式在绿色化学的发展中具有光明的前景。可见光是一种可再生的资源,可见光催化符合绿色合成、环境友好和可持续发展的理念,在有机合成领域中引起了广泛的关注。建立在光诱导的单电子转移过程的基础上,可见光催化为实现温和条件下构建化学键提供了一种新的思路。虽然很多的有机分子不能有效吸收可见光,但是利用可见光催化剂(光敏剂)在电子和能量转移过程中的独特优势,能够有效实现在可见光作用下的一系列光化学反应。光催化是有机合成构建新物质的一种有效的手段,随着光催化在有机合成领域中的发展,一系列新型温和而有效的可见光催化的氧化偶联反应也逐渐被报道。虽然过渡金属催化的氧化偶联反应已经取得了重大的进展,但是利用可见光催化的策略以实现两个亲核试剂之间化学键的构建作为一个新的领域,近年来才刚刚发展起来。尤其是结合可见光催化条件温和、环境友好的特点和氧化偶联反应的原子经济性特点,将可见光诱导的单电子转移过程运用到交叉脱氢偶联反应,引起了广泛的关注。光催化氧化偶联反应不仅解决了传统偶联中的步骤经济性和原子经济性的问题,同时也具备了可见光反应温和环保的特点。近几年来已经发展了多种类型的光催化氧化偶联反应,包括光催化氧化含氮化合物的偶联反应、光催化氧化脱羧偶联反应、以及光催化交叉偶联放氢反应等。但是在光催化氧化偶联领域的相关报道大多局限于含氮化合物和易氧化的底物的活化氧化,因此任然存在着很多的挑战。本文总结了最近几年来的不同反应类型的可见光催化的氧化偶联的研究和进展。而对这些反应的理解和认识,可以为人们发展更多的高效率和高选择性的可见光催化氧化偶联反应提供帮助。     

Iron-catalysed, hydride-mediated reductive cross-coupling of vinyl halides and Grignard reagents

An iron-catalysed, hydride-mediated reductive cross-coupling reaction has been developed for the preparation of alkanes. Using a bench-stable iron(II) pre-catalyst, reductive cross-coupling of vinyl iodides, bromides and chlorides with aryl- and alkyl Grignard reagents successfully gave the products of formal sp(3)-sp(3) cross-coupling reactions.     

镍催化偶联反应机理研究进展(英文)

近期发展了很多镍催化的偶联反应作为在有机合成中高效构建C–C键的方法,同时开展了很多关于控制镍催化反应活性和选择性的机理研究.这些研究发现,镍催化反应机理往往和相应的钯催化反应机理不同,因为镍催化偶联经常包括自由基和双金属机理.本文总结了镍催化偶联反应机理的最新进展.对于这些反应机理的理解为发展具有更高效率和选择性的镍催化偶联反应提供了帮助.     

Pd(PPh3)2Cl2-CuCl体系催化有机高价碘杂环化合物与末端炔烃的化学选择性交叉偶联反应

以有机高价碘杂环化合物1,2为底物,在Pd(PPh3)2Cl2-CuCl催化剂存在下与末端炔烃进行交叉偶联反应,实验发现该反应为--化学选择性反应,控制反应体系的物料比、温度及反应时间可以分别得到单偶联或双偶联产物,从而证实了有机高价碘杂环化合物的碘盐在进行交叉偶联反应时的反应活性比sp2的碘化物高.     

Total syntheses of the thiopeptides amythiamicin C and D

The thiopeptides amythiamicin C and D were synthesized by employing amide bond formation, a Stille cross-coupling reaction, and two Negishi cross-coupling reactions as key transformations. The central 2,3,6-trisubstituted pyridine ring of the target compounds was introduced as a 2,6-dibromo-3-iodopyridine, which was selectively metalated at the 3-position and connected to the complete Southern fragment of the amythiamicins by a Negishi cross-coupling. For the synthesis of amythiamicin C, this step was followed by a Negishi cross-coupling at C-6 of the pyridine core. Subsequent attachment of the Eastern fragment was achieved by amide bond formation and macrolactam ring closure by a Stille cross-coupling at C-2. The Eastern bithiazole fragment of the amythiamins was constructed also by regioselective metalation and cross-coupling reactions. The pivotal step involved the diastereoselective addition of 4-bromothiazole-2-magnesium bromide to a chiral sulfinyl imine. For the synthesis of amythiamicin D, the order of cross-coupling at C-6, amide bond formation, and cross-coupling at C-2 was changed. The amide bond formation to the Eastern fragment was performed first and it was subsequently attempted to close the macrolactam by an intramolecular regioselective Stille cross-coupling at C-2. Despite the low regioselectivity of this reaction it paved the way to the immediate completion of the amythiamicin D synthesis when followed by a Negishi cross-coupling at C-6 with 2-zincated methyl thiazole-5-carboxylate.     

光催化Suzuki偶联反应的非均相催化剂研究进展

Suzuki偶联反应作为构建C-C键的最有效的手段之一,在医药、染料和电子工业等领域扮演着重要的角色.近年来,光催化技术和绿色有机合成化学蓬勃发展,利用可再生的太阳能光催化Suzuki偶联反应不但可以解决在催化反应过程中的能源与环境问题,还可以在温和条件下高产率地获得联苯化合物.与均相光催化剂相比,非均相光催化剂具有良...     

胺作为配体在钯催化偶联反应中应用

对近期我们研究小组及其它研究小组在利用胺作为钯催化偶联反应的配体研究进展进行了总结. 钯/胺作为催化体系主要应用的偶联反应包括: Suzuki-Miyaura交叉反应, Sonogashira交叉反应, Stille交叉反应, Hiyama交叉反应和Heck反应. 研究结果表明胺可以作为价廉和高效的配体促进钯催化交叉偶联反应.     

Palladium-catalyzed cross-coupling reactions of aryl mesylates

Palladium-catalyzed cross-coupling reactions are state-of-the art methods for synthesis of many important compounds. The development of the use of the phenol-derived sulfonated hydroxyl group in the coupling reactions is highly attractive as the hydroxyl group is commonly present in organic compounds and they are versatile alternatives to aryl halides in cross-coupling reactions. In this tutorial review, we summarize the current development of palladium-catalyzed cross-coupling reactions of aryl mesylates.     

Transition metal catalyzed cross-coupling of aryl Grignard reagents with aryl fluorides via Pd- or Ni-activation of the C-F bond: an efficient synthesis of unsymmetrical biaryls - application of microwave technology in ligand and catalyst screening

Biaryl compounds are prevalent in both nature and in active pharmaceutical ingredients. The palladium and nickel catalyzed cross-coupling of aryl Grignard reagents with aryl fluorides reported herein affords moderate to excellent yields of the corresponding unsymmetrical biaryls. In addition, the first example of a biaryl cross-coupling utilizing unactivated aryl fluorides under phosphine free palladium conditions is reported. Microwave technology allowed rapid optimization of catalyst systems, which identified several ligands for this cross-coupling reaction.     

过渡金属催化氟代烯烃参与的交叉偶联反应进展

过渡金属催化（类）卤化物和不同金属试剂的交叉偶联反应是构建不同类型碳碳键和碳杂原子键的重要方法之一。该类反应一般使用活性较高的氯、溴、碘或类卤化物作为亲电试剂,尽管C—F键的键能较强,利用过渡金属直接活化较为惰性的芳基C—F键并参与实现的交叉偶联反应已有较多报道。此外,近期的研究表明,也可以通过直接活化烯基C—F键并催化实现该类底物参与不同类型的交叉偶联反应,从而进一步拓展了交叉偶联反应的底物适用范围,并应用于具有高附加值精细化学品的选择性合成。本文围绕钯或镍催化活化单氟或者多氟烯烃等底物参与的Negishi、Suzuki-Miyaura、Kumada、Hiyama和Sonogashira等5类交叉偶联反应,通过探讨已有方法的反应机理及其适用范围,综述了该领域的研究进展并进行了展望。     

Glycerol as a promoting medium for cross-coupling reactions of diaryl diselenides with vinyl bromides

We described herein the use of glycerol as a novel solvent in the cross-coupling reaction of diaryl diselenides with vinyl bromides catalyzed by CuI. This cross-coupling reaction was performed with diaryl diselenides and (Z)- or (E)-vinyl bromides bearing electron-withdrawing and electron-donating groups, affording the corresponding vinyl selenides in good to excellent yields. The mixture glycerol/catalyst can be directly reused for further cross-coupling reactions.     

The first Cu- and amine-free Sonogashira-type cross-coupling in the C-6-alkynylation of protected 2′-deoxyadenosine

The Sonogashira cross-coupling reaction offers a convenient route to C(sp)-C(sp²) bond formation. Although the Sonogashira reaction has traditionally been carried out in the presence of Pd catalyst and a co-catalyst of Cu(I) salt, the use of Cu(I) salt is often not efficient because it leads to the formation of unwanted side-products. This has prompted interest in recent years in the development of Cu-free Sonogashira cross-coupling reaction conditions. In addition, the development of Cu-free Sonogashira cross-coupling conditions for the alkynylation of nucleoside derivatives remains largely unexplored. Herein, we demonstrate that Cu- and amine-free Sonogashira-type cross-coupling lead to successful alkynylation of aryl bromides and heteroaryl bromides. For the first time, we have extended this method for the alkynylation of protected 2′-deoxyadenosine at the C-6 position.     

Nickel-catalyzed migratory alkyl–alkyl cross-coupling reaction

The selective cross-coupling of activated electrophiles with unactivated ones has been regarded as a challenging task in cross-electrophile couplings. Herein we describe a migratory cross-coupling strategy, which can overcome this obstacle to access the desired cross-coupling products. Accordingly, a selective migratory cross-coupling of two alkyl electrophiles has been accomplished by nickel catalysis. Remarkably, this alkyl–alkyl cross-coupling reaction provides a platform to prepare 2°–2° carbon–carbon bonds from 1° and 2° carbon coupling partners. Preliminary mechanistic studies suggest that chain-walking occurs at both alkyl halides in this reaction, thus a catalytic cycle with the key step involving two alkylnickel(ii) species is proposed for this transformation.

The selective cross-coupling of activated electrophiles with unactivated ones has been regarded as a challenging task in cross-electrophile couplings.     

可见光直接促进的过渡金属催化交叉偶联反应研究进展

经过几十年的发展,过渡金属催化的交叉偶联反应已经成为一类功能强大的有机合成方法,广泛应用于各种碳碳键和碳杂原子键的高效构建.最近几年化学家们发现在越来越多的情况下,不用外加光敏剂,可见光能直接促进过渡金属催化的交叉偶联反应,使原来无法发生或缓慢进行的偶联反应得以顺利实现.该类反应因条件简单、反应温和以及无需外加光敏剂等优点受到了广泛的关注.根据过渡金属的分类,综述了近些年来该类反应的研究进展.     

Reactions of organic halides with organometallic compounds and terminal acetylenes catalyzed by palladium complexes

The results of the investigation of the cross-coupling of organometallic compounds and terminal acetylenes with organic halides catalyzed by transition metal complexes are generalized and analyzed. The influence of different factors on the rate and selectivity of catalytic cross-coupling is discussed. A detailed mechanism of the cross-coupling of Grignard reagents with organic halides is suggested. The cross-coupling reaction involving organotin compounds proceeds under very mild conditions in the presence of a ligand-free Pd catalyst. Examples of using catalytic cross-coupling of organic halides with organomagnesium, organozinc, and organotin compounds are presented.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 2148–2167, September, 1996.     

Orthogonal reactivity in boryl-substituted organotrifluoroborates

A method was developed for the hydroboration of alkenyl-containing organotrifluoroborates to generate dibora intermediates. The reactivity differences between organotrifluoroborates and trialkylboranes facilitated the cross-coupling of the borane moiety of these intermediates in a highly chemoselective fashion with aryl halides, leaving the trifluoroborate intact for subsequent transformation. A one-pot hydroboration/two-directional cross-coupling sequence was also demonstrated, providing the fully elaborated products in good yields. These conditions were also amenable in the cross-coupling of trialkylboranes to halo-containing organotrifluoroborates. The stability of the trifluoroborate moiety to these conditions allows simple and efficient strategies for complex molecule construction.     

CuMoO4 Bimetallic Nanoparticles,An Efficient Catalyst for Room Temperature C−S Cross-Coupling of Thiols and Haloarenes

Cu^II catalyst is less efficient at room temperature for C−S cross-coupling. C−S cross-coupling by Cu^II catalyst at room temperature is not reported; however, doping of copper with molybdenum metal has been realized here to be more efficient for C−S cross-coupling in comparison to general Cu^II catalyst. The doped catalyst CuMoO₄ nanoparticle is found to be more efficient than copper. The catalyst works under mild conditions without any ligand at room temperature and is recyclable and effective for a wide range of thiols and haloarenes (ArI, ArBr, ArF) from milligram to gram scale. The copper-based bimetallic catalyst is developed and recognized for C−S cross-coupling of haloarenes with alkyl and aryl thiols.     

Pd-P(t-Bu)(3)-catalyzed consecutive cross-coupling of p-phenylenedizinc compound with two different electrophiles leading to unsymmetrically 1,4-disubstituted benzenes

Pd-P(t-Bu)3 was found to be a chemoselective catalyst for the reaction of p-phenylenedizinc compound with equimolar amounts of carbon electrophiles to afford the single cross-coupling products in good yields, effectively suppressing the formation of double cross-coupling products. The subsequent additions of other electrophiles to the resulting solutions caused the second cross-coupling of the incipient products to take place, achieving a novel and efficient one-pot synthesis of unsymmetrically 1,4-disubstituted benzenes. The origin of the observed high chemoselectivity was speculated.