Cyanosilylation of Aldehydes Catalyzed by Ag(I)- and Cu(II)-Arylhydrazone Coordination Polymers in Conventional and in Ionic Liquid Media

Abstract

The novel Ag(I) and Cu(II) coordination polymers [Ag(μ3-1κO;2:3κO′;4κN-HL)]n∙n/2H2O (1) and [Cu(en)2(μ-1κO;2κN-L)]n∙nH2O (2) [HL− = 2-(2-(1-cyano-2-oxopropylidene)hydrazinyl)benzene sulfonate] were synthesized and characterized by IR and ESI-MS spectroscopies, elemental and single crystal X-ray diffraction analyses. Compounds 1 and 2 as well as the already known complex salt [Cu(H2O)2(en)2](HL)2 (3) have been tested as homogenous catalysts for the cyanosilylation reaction of different aldehydes with trimethylsilyl cyanide, to provide cyanohydrin trimethylsilyl ethers. Coordination polymer 2 was found to be the most efficient one, with yields ranging from 76 to 88% in methanol, which increases up to 99% by addition of the ionic liquid [DHTMG][L-Lactate].

Improved Performance of a Europium‐based Metal‐Organic Framework for Cyanosilylation of Demanding Ketones

“…[1] For the synthesis of this type of compounds, trimethylsilyl cyanide (TMSCN) has been imposed in order to replace the use of more toxic reagents such as NaCN, KCN or HCN, giving rise to the generation of the CÀ C bond with a greenest approach. [2] This is a preferred reagent due to its easy handling and most importantly, its higher atom economy without formation of side products. Moreover, it is environmentally friendly, cost-efficient and selective towards extremely versatile organic molecules, which is in total agreement with some of the twelve principles of green chemistry.…”

“…Moreover, it is environmentally friendly, cost-efficient and selective towards extremely versatile organic molecules, which is in total agreement with some of the twelve principles of green chemistry. [3] Several efficient catalysts such as Lewis acids, [4,5] Lewis bases, [6,7] organic-inorganic salts, [8,9] or nucleophilic catalysts [10] among others [2] have been extensively investigated so far in the cyanosilylation reaction. All of which can play an important role in the activation of the carbonyl-containing substrates.…”

“…Cyanohydrins are versatile building blocks for the synthesis of a great variety of fine chemicals, agrochemicals and pharmaceuticals [1] . For the synthesis of this type of compounds, trimethylsilyl cyanide (TMSCN) has been imposed in order to replace the use of more toxic reagents such as NaCN, KCN or HCN, giving rise to the generation of the C−C bond with a greenest approach [2] . This is a preferred reagent due to its easy handling and most importantly, its higher atom economy without formation of side products.…”

“…Several efficient catalysts such as Lewis acids, [4,5] Lewis bases, [6,7] organic‐inorganic salts, [8,9] or nucleophilic catalysts [10] among others [2] have been extensively investigated so far in the cyanosilylation reaction. All of which can play an important role in the activation of the carbonyl‐containing substrates.…”

Metal‐Organic Frameworks as Platform for Lewis‐Acid‐Catalyzed Organic Transformations

“…Cyanohydrins are considered as versatile building blocks for fine chemicals, agrochemicals and pharmaceuticals, that is, α‐hydroxyacids, β‐hydroxyamines, α‐aminonitriles, α‐hydroxyketones and β‐aminoalcohols . In contrast to other toxic substances such as KCN, HCN and NaCN, TMSCN is a preferred reagent for cyanosilylation reaction as it is easy to handle, the Si−C bond has low dissociation energy and most importantly it has high atom economy without giving side reactions . There are plenty of reports available on MOF catalyzed cyanosilylation reaction with a classic report from Prof. Fujita's group on a cadmium‐MOF in 1994, being the first one .…”