Gallium (III) triflate catalyzed efficient Strecker reaction of ketones and their fluorinated analogs

Abstract

The synthesis of ␣-aminonitriles and their fluorinated analogs has been carried out in high yield and purity by the Strecker reaction from the corresponding ketones and amines with trimethylsilyl cyanide using gallium triflate in dichloromethane. Monofluoro-, difluro-, or trifluoromethyl groups can be incorporated into the ␣-aminonitrile product by varying the nature of the fluorinated ketones. Study with various fluorinated and nonfluorinated ketones reveals that the choice of proper catalyst and the solvent system (suitable metal triflates as a catalyst and dichloromethane as a solvent) plays the key role in the direct Strecker reactions of ketones.three-component reaction ͉ ␣-aminonitriles

Synthesis of α‐Amino Nitriles from Carbonyl Compounds, Amines, and Trimethylsilyl Cyanide: Comparison between Catalyst‐Free Conditions and the Presence of Tin Ion‐Exchanged Montmorillonite

“…Sn-Mont (10 mg; Sn: 1.9 mol-%), however, gave 5a in an 84 % isolated yield within three hours (entry 2). The TOF reached 67.4 h -1 , which is higher than that obtained with Ga(OTf) 3 (3.92 h -1 ) [25] and comparable to that using Fe(Cp) 2 PF 6 (57 h -1 ) [24] as homogeneous catalysts. In contrast, when the reaction was performed with pristine Na-Mont, Sn(OH) 4 prepared from SnCl 4 with aqueous NH 3 , or crystalline SnO 2 , almost no reaction occurred (Table 3, entries 3-5).…”

“…The direction of the overall reaction depends www.eurjoc.orgon the relative rates of the two pathways; the addition of amines to ketones (hemiaminal/imine formation) or TMSCN addition to ketones (cyanohydrin formation). [25] With aromatic amines such as aniline, in the presence of Sn-Mont, the imine formation is far faster than that of cyanohydrin, preferentially producing α-amino nitrile. However, with aliphatic amines and aromatic ketones, the more basic aliphatic amines act as homogeneous base catalysts to promote the nucleophilic addition of TMSCN to ketones to provide the cyanohydrin derivatives, [42] the formation rate of which is much higher than that of the corresponding imine from ketones and aliphatic amines catalyzed by SnMont.…”

“…[23] Recently Khan [24] reported Fe(Cp) 2 PF 6 as a homogeneous catalyst for the reaction with ketones, whereas Olah used Ga(III) triflate and (CH 3 ) 3 SiOSO 2 CF 3 in dichloromethane. [11,25] More recently, Jung and coworkers reported using the Strecker reactions with ketones; in this case the reaction was catalyzed by palladium(II) complex and required 24 hours. [26] Thus, the aim of this study was to develop a mild, efficient, heterogeneous catalytic system for performing Strecker reactions that is particularly suitable for ketones.…”

An expeditious and greener one-pot synthesis of 4H-chromenes catalyzed by Ba(OTf)2in PEG-water

“…Metal triflates are an attractive alternative because of their low toxicity, noncorrosive nature, safety, ease to handle, recovery, and separability. Metal triflates are efficient and mild green Lewis acid catalysts that function in a variety of reaction (20,21). Unlike traditional Lewis acids they are required in catalytic amount and are stable in presence of water.…”

Synthesis and Characterization of New Complexes of (N-P-Amino Diphenyl Amine) Amino (2-Hydroxy Phenyl) Acetonitrile Ligand with Some Transition Metal Ions

“…Notable among them are HCN [14], KCN [15], (EtO) 2 P(O)CN [16,17], Et 2 AlCN [18,19], Bu 3 SnCN [20,21], and Me 3 SiCN [22]. Recently, several modifications of the Strecker reaction using catalysts have been reported which includes mesoporous aluminosilicate (Al-MCM-41) [23], lanthanum(III)-binaphthyl disulfonate [24], nanocrystalline magnesium oxide [25], BINOL-phosphoric acid [26,27], Fe(Cp) 2 PF 6 catalyst [28], Jacobsen's thiourea catalyst [29], N-heterocyclic carbine (NHC)-amidate palladium(II) complex [30],Yb(OTf) 3 -pybox [31], K 2 PdCl 4 catalyst [32], gallium (III) triflate [33], bisformamides [34], superparamagnetic iron oxide [35], Trimethylsilyl Cyanide -Iodine catalyst [36], Trimethylsilyl Cyanide-p-Toluene sulphonic acid [37] , homogeneous and solidsupported promoter [38] and K 5 CoW 12 O 40 .3H 2 O as heterogeneous catalyst [39].Finally, an efficient and practical method for the Strecker reaction under eco-friendly conditions have been achieved to processed organic reactions in water or ionic liquid in the view of green methodologies [40][41][42][43].In this work α-aminonitriles have often been used as chelating ligands through two nitrogen atoms in the field of coordination chemistry.This is one of the first studies to reveal a new coordination field of α-aminonitrile compounds as ligands and their interactions with transition metal ions.…”