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

Abstract

In the absence of catalysts, the three-component, one-pot synthesis of α-amino nitriles proceeded using various aldehydes and ketones together with amines and trimethylsilyl cyanide (TMSCN) in high yields under neat conditions at room temperature. The addition order of the reagents had a significant influence on the yields of the desired α-amino nitriles. In contrast, when tin ion-exchanged montmorillonite (Sn-Mont), prepared by the ion-exchange of sodium montmorillonite (Na-Mont) with a tin tetrachloride solution, was used as a catalyst, the reaction rates significantly increased compared with those without catalysts, and the range of the applicable carbonyl compounds was also extended: structurally diverse aromatic, aliphatic and heteroatom-containing carbonyl compounds, including sterically hindered ketones

SO42−/Sn-MMT Solid Acid Catalyst for Xylose and Xylan Conversion into Furfural in the Biphasic System

“…MMT is able to intercalate various ions into the interlayer spaces, which would influence the interlayer distance [20]. The 001 reflection of the XRD patterns showed the basal spacing of MMT ( Figure 1).…”

Insights into the Nature of the Active Sites of Tin‐Montmorillonite for the Synthesis of Polyoxymethylene Dimethyl Ethers (OME)

“…[25] They later found that its high specific surface area was formed by the intercalation of SnO 2 nanoparticles between clay layers, resulting in strong Brønsted and Lewis acidity. [26][27][28] Sn-MMT was also found to display a disorganized "house-of-cards" structure. [23] The coexistence of acid sites was leveraged for various hemicellulose upgrading reactions: conversion of carbohydrates to 5-(hydroxymethyl) furfural (HMF), [29] HMF self-etherification, [24] synthesis of alkyl lactates from triose [30] and the production of furfural from xylose.…”

“…reported that Sn‐MMT displayed a highly superior activity than Sn‐grafted MCM‐41 for the cyanosilylation of ketones . They later found that its high specific surface area was formed by the intercalation of SnO 2 nanoparticles between clay layers, resulting in strong Brønsted and Lewis acidity . Sn‐MMT was also found to display a disorganized “house‐of‐cards” structure .…”

Efficient Nucleophilic Substitution of α-Aryl Alcohols with 1,3-Dicarbonyl Compounds Catalyzed by Tin Ion-Exchanged Montmorillonite

“…25,28 Thus, the reaction pathway in the nucleophilic substitution of al- 20 followed by the direct attack with 1,3-dicarbonyl compounds to form the alkylated 1,3-dicarbonyl derivatives.…”