Silica‐supported perchloric acid as a recyclable catalyst for efficient trimethylsilyl cyanide addition to aldehydes

Abstract

HClO 4 -SiO 2 (0.6 mol%) acts as a highly effective catalyst for cyanation of various aldehydes to the corresponding O-trimethylsilyl cyanohydrins, in high yields and short reaction times.

Solvent-Free Achiral Cyanosilylation of Aldehydes and Ketones Catalyzed by LiNTf2

“…Cu(ClO 4 ) 2 •6H 2 O [5] , HClO 4 /SiO 2 [6] , 氮杂环卡宾 [7] , LiCl/ THF [8] , Au [9] , SbCl 3 [10] , [(Ph 3 P) 2 N] ＋ Cl - [11] , Sc(OTf) 3 [12] , NbF 5 [13] , MgO [14] , SO 4 2-/ZrO 2 [15] , ZnI 2 [16] 和 LiClO 4 [17] 等. 虽然以上催化剂都取得了一定的效果, 但是有的催化剂 催化的硅氰化反应存在反应时间长、催化剂用量多和使 用有机溶剂等缺点.…”

Perchloric Acid and Its Salts: Very Powerful Catalysts in Organic Chemistry

“…The cyanation reaction of carbonyl compounds is one of the most powerful procedures for the synthesis of polyfunctional molecules, and the synthesis of cyanohydrins is another typical acid-catalyzed carbonyl addition reaction. Both HClO 4 −SiO 2 (0.6 mol %) and stoichiometric solid LiClO 4 act as highly effective catalysts (88−98% and 90−100% yields, respectively) for cyanation of various aldehydes to the corresponding O -trimethylsilyl cyanohydrins with trimethylsilylcyanide. Actually, only LiClO 4 catalysis can be efficiently extended to ketones (85−98%) (Scheme ) …”

Protic Acid Immobilized on Solid Support as an Extremely Efficient Recyclable Catalyst System for a Direct and Atom Economical Esterification of Carboxylic Acids with Alcohols

“…We were delighted to observe that soon after the original work on its invention Chakraborti’s novel catalyst system HClO 4 −SiO 2 , caught the attention of other researchers globally who started applying HClO 4 −SiO 2 as catalyst for a large variety of organic reactions/syntheses (e.g., amidoalkylation of naphthols, construction of heterocyclic scaffolds, homoallyl amines, α-bromo and β-amino/sulfido carbonyl compounds, trisubstituted alkenes, acylals, carbohydrates, etc.) . We now report HClO 4 −SiO 2 as an extremely efficient and reusable catalyst system for a general and practical esterification process by direct condensation of carboxylic acids with alcohols in atom economical fashion…”