SiO2·p-TSA: a green catalyst for solvent-free tetrahydropyranylation of alcohols and thiols

Abstract

Foi desenvolvido um procedimento para tetrahidropiranilação de álcoois e tióis em ausência de solvente orgânico, baseado na simples mistura dos reagentes, na presença de sílica gel e quantidade catalítica de p-TSA.A solvent-free procedure for tetrahydropyranylation of alcohols and thiols based on a simple grinding of the reagents in the presence of silica gel and catalytic amounts of p-TSA is described.

Solvent-free catalysed synthesis of tetrahydropyran odorants: the role of SiO

“…-2-phenyltetrahydro-2H-pyran-4-ol (5) Syn 3,40.1,48.4,66.0,69.2,77.7,125.9,127.6,128.5, 8,38.5,46.6,64.1,68.1,75.2,125.9,127.4,128.4,.…”

“…69 (100) (E) tetrahydro-2H-pyran-4-ol (7g) Syn diastereoisomer: Eluent: hexane/ethyl acetate (2:1), Rf 0.60; colorless oil, yield 25%; 1 9,27.7,39.7,46.4,58.4,73.2,75.1,128.0,133.9; 8,31.8,38.4,44.7,63.5,67.8,73.5,127.2,131.9;.…”

Tuning Acidity of Sulfonated Mesoporous Polymers (MP−SO3H) for Efficient Tetrahydropyranylation of Alcohols at Room Temperature

“…Recently, metal oxides, ,[23,24,25,26] MOFs Ionic liquids and porous polymers ,[32,33,34,35] are also being explored for catalytic applications. Heterogeneous catalysts such as natural clays, ion‐exchange resins, silica‐based sulfonic acid, Fe 3 O 4 @SiO 2 @SO 3 H, polyaniline sulfate, carbon‐based solid acid, SiO 2 ‐ p ‐TSA, zeolites etc have been extensively investigated for tetrahydropyranylation of alcohols. However, many of the catalysts show lower catalytic activity except few catalysts which have shown exceptional catalytic activities.…”

Catalytic tetrahydropyranylation of phenols and alcohols using vanadium(V)-substituted polyoxomolybdates

“…Tetrahydropyranylation of alcohols can be accomplished using p-toluenesulfonic acid (p-TSA), 2 BF 3 ·OEt 2 3 and pyridinium ptoluenesulfonate (PPTS). 4 Recently, some developed reagents have been used for this purpose, such as ZrCl 4 , 5 I 2 , 6 LiBr, 7 acetonyltriphenylphosphonium bromide, 8 tetrabutylammonium tribromide (TBATB), 9 aluminium chloride hexahydrate, 10 indium(III) trifluoromethanesulfonate (In(OTf) 3 ), 11 alkylimidazolium tetrachloroaluminates, 12 InCl 3 immobilized in ionic liquids, 13 polystyrene-bound tin(IV) porphyrin, 14 Dowex 50WX4-100, 15 pyridinium chloride, 16 SiO 2 ·p-TSA, 17 N,N'-bis [3,5-bis(trifluoromethyl)phenyl]thiourea and a polystyrene-bound analogue, 18 Al(OTf) 3 , 19 and bromodimethylsulphonium bromide. 20 The employment of protective groups is an important procedure in organic synthesis.…”