Selective Ruthenium‐Catalyzed Hydration of Nitriles to Amides in Pure Aqueous Medium Under Neutral Conditions

Cadierno, Victorio; Francos, Javier; Gimeno, José

doi:10.1002/chem.200800847

Cited by 167 publications

(95 citation statements)

References 48 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Remarkably, the corresponding hexamethylbenzene derivatives proved to be also the most active within the series of complexes 20 discussed above (Fig. 6) [30]. Since an increase of the steric bulk of the η 6 -arene ligand would lead to an increase in the rate of ligand dissociation, the rate-determining step in these hydration reactions may be the dissociation of the amide from the metal.…”

Section: Homogeneous Ruthenium-based Catalystsmentioning

confidence: 88%

“…In order to facilitate the solubility of the catalysts in water, remarkable efforts have been devoted in recent years to the study of ruthenium complexes bearing water-soluble phosphines. In this context, a possible cooperative effect of the "cage-like" phosphines PTA, PTA-Bn, DAPTA, THPA and THDP [29], via H-bonding of the nucleophilic water molecule with the nitrogen atoms present in their structures, has been proposed to explain the remarkably higher effectiveness shown by the arene-ruthenium(II) 20 [30] and bis(allyl)-ruthenium(IV) complexes 21-22 [31] in comparison with the related species 23-24 bearing the sulphonated phosphine TPPMS, in which such an interaction cannot be established (Fig. 6).…”

Section: Homogeneous Ruthenium-based Catalystsmentioning

confidence: 99%

See 1 more Smart Citation

Metal-catalyzed nitrile hydration reactions: The specific contribution of ruthenium

Garcı́a-Álvarez

Francos

Tomás‐Mendivil

et al. 2014

Journal of Organometallic Chemistry

Self Cite

View full text Add to dashboard Cite

The hydration of nitriles is an atom economical route to generate primary amides of great academic and industrial significance. From an academic perspective, considerable progress has been made toward the development of transition metal catalysts able to promote this hydration process under mild conditions. In this context, with regard to activity, selectivity, functional group compatibility and modes of reactivity, the most versatile nitrile hydration catalysts discovered to date are based on ruthenium complexes. Herein, a comprehensive account of the different homogeneous ruthenium catalysts described in the literature is presented. Heterogeneous ruthenium-based systems are also discussed.

show abstract

Section: Homogeneous Ruthenium-based Catalystsmentioning

confidence: 88%

Section: Homogeneous Ruthenium-based Catalystsmentioning

confidence: 99%

Metal-catalyzed nitrile hydration reactions: The specific contribution of ruthenium

Garcı́a-Álvarez

Francos

Tomás‐Mendivil

et al. 2014

Journal of Organometallic Chemistry

Self Cite

View full text Add to dashboard Cite

show abstract

“…[17] To overcome these issues, we surmised that a water-soluble ligand might connect the metal precursor and substrates in the aqueous phase, and that hydrolysis of the nitriles could be somewhat inhibited by choosing an appropriate temperature. Very recently, we reported an iron-catalyzed [2+2+2] cycloaddition of alkynes and nitriles involving an in situ-generated iron catalyst.…”

mentioning

confidence: 99%

Ruthenium‐catalyzed [2+2+2] Cycloaddition of Diynes with Nitriles in Pure Water

Wang

et al. 2012

ChemSusChem

View full text Add to dashboard Cite

The transition metal-catalyzed [2+2+2] cycloaddition of two alkyne molecules and a nitrile, particularly involving catalysis by Co, Ru, Rh, Ni, Ti, and Fe species, [1][2][3][4][5][6] has been widely investigated as a valuable tool for the synthesis of substituted pyridines. [7,8] However, highly diluted conditions and techniques of slow addition are generally required to suppress the competing side reactions, such as dimerization and trimerization of the diynes. [9a] Despite substantial advances, metal-catalyzed [2+2+2] cycloaddition remains a formidable challenge. Thus, new tactics should be applied to the reaction, aimed at attenuating or controlling the side reactions. It has been shown that the Diels-Alder reaction can be intensified in aqueous media, [9b] and we expect that water can also expedite the [2+2+2] cycloaddition.Although the [2+2+2] cycloaddition reaction has been widely explored in the last few decades, there are only limited examples of the use of water as solvent (Scheme 1). Heller and co-workers reported that acetylene and nitriles in water efficiently undergo co-cyclization under visible-light irradiation in the presence of CpCo(COD) (COD: 1,5-cyclooctadiene) and its derivatives, resulting in excellent product selectivities and moderate yields. [10] Parsons and Jerome reported a reaction of hexyne and acetonitrile in supercritical water at 374 8C, affording the corresponding pyridine isomers in a yield of 15 %. [11] Eaton and co-workers showed that a water-soluble cobalt complex catalyzes the [2+2+2] cycloaddition of two alkyne molecules and a nitrile in a mixture of water and methanol at 85 8C, with a yield of up to 99 %. However, hydrophilic functional groups on the alkynes were necessary. [12] In 2002, Butenschçn reported another cobalt complex with pendant phosphane substituents on the cyclopentadienyl ring. These substituents made the cobalt complex stable in water, thus allowing the preparation of pyridine derivatives at room temperature in a mixture of water and ethanol. [13] In aqueous medium, acceleration of the cycloaddition by water should outweigh the lowered efficiency and reaction rate due to the highly dilute reaction conditions. [9] In addition, water can induce rate enhancements, [14] chemoselectivity, [15] and stereoselectivity [16] in numerous synthetic transformations. However, to the best of our knowledge mixed solvents or photochemical activation were necessary in previous works, and the cycloaddition of diynes and a nitrile in neat water without irradiation has never been reported. The development of a new catalytic system to circumvent these restrictions is still highly desirable.Generally, two crucial problems are encountered in the [2+2+2] cycloaddition of alkynes and nitriles in water: 1) the poor solubility of the metal precursor and substrates in pure water, and 2) easy hydrolysis of the nitriles in water under the reaction conditions. [17] To overcome these issues, we surmised that a water-soluble ligand might connect the metal precursor and substrates in th...

show abstract

“…More likely, the intrinsic basic nature of the pendant amino group of the aryl-phosphines would increase the concentration of the more nucleophilic hydroxide anion in the solution, thus accelerating the hydration process ( Figure 2). The use as auxiliary ligands derived from the aminophosphine PTA (1,3,5-triaza-7-phosphaadamantane) and related water-soluble "cage-like" phosphines has led in recent years to highly efficient ruthenium catalysts for nitrile hydration in pure water [40][41][42][43][44]. Complexes 4-8 are the most representative examples (Figure 3).…”

Section: Scheme 5 Catalytic Hydration Of Nitriles Using Cis-[ru(acacmentioning

confidence: 99%

“…However, very long reaction times of 97 (5) [42] and 14 (6) [44] days were needed to achieve such a high productivity. It is also worthy of note that, after selective crystallization of the final amides, recycling of the aqueous phase containing complexes 4 (2 times) [40] and 5 (6 times) [42] was possible. The arene-ruthenium(II) complex 9, bearing the water-soluble and potentially H-bond acceptor ligand tris(5-(2-aminothiazolyl))-phosphine trihydrochloride (Figure 3), featured also a high activity (TOF up to 66 h -1 ), productivity (TON up to 9800), substrate scope and functional group tolerance, combined with an effective recycling (up to five consecutive runs) [45].…”

Section: Scheme 5 Catalytic Hydration Of Nitriles Using Cis-[ru(acacmentioning

confidence: 99%

Ruthenium-Catalyzed Amide-Bond Formation

Crochet

Cadierno

2014

Ruthenium in Catalysis

Self Cite

View full text Add to dashboard Cite

The amide functionality is one of the most important functional groups in organic and biological chemistry. Classical synthetic strategies of amides involve the stoichiometric, and poor atom efficient, reaction of amines with carboxylic acid derivatives. Transition-metal-catalyzed reactions have emerged in recent years as more atom-economical and powerful tools for preparing amides, opening previously unavailable routes from substrates other than the carboxylic acids and their derivatives. Ruthenium-based catalysts have been at the heart of these advances, and this chapter pretends to give an overview of the field. Among others, the following ruthenium-catalyzed synthetic approaches of amides will be discussed: the hydration of nitriles, the hydrolytic amidation of nitriles with amines, the rearrangement of aldoximes, the coupling of aldehydes with hydroxylamine, and the dehydrogenative amidation of alcohols, aldehydes and esters.

show abstract

Selective Ruthenium‐Catalyzed Hydration of Nitriles to Amides in Pure Aqueous Medium Under Neutral Conditions

Cited by 167 publications

References 48 publications

Metal-catalyzed nitrile hydration reactions: The specific contribution of ruthenium

Metal-catalyzed nitrile hydration reactions: The specific contribution of ruthenium

Ruthenium‐catalyzed [2+2+2] Cycloaddition of Diynes with Nitriles in Pure Water

Ruthenium-Catalyzed Amide-Bond Formation

Contact Info

Product

Resources

About