Succinimide-N-Sulfonic Acid: A Mild,Efficient, and Reusable Catalyst for the Chemoselective Trimethylsilylation of Alcohols and Phenols

Abstract

Succinimide-N-sulfonic acid (SuSA) is easily prepared by the reaction of succinimide with chlorosulfonic acid. This reagent is able to efficiently catalyze the chemoselective trimethylsilylation of alcohols and phenols with hexamethyldisilazane (HMDS). All reactions were performed under mild reaction conditions, giving excellent yields.

GRAPHICAL ABSTRACT      

A Mild and Efficient Method for Chemoselective Silylation of Alcohols Using Hexamethyldisilazane in the Presence of Silica Chloride

Reaction of alcohols with hexamethyldisilazane in the presence of silica chloride provides efficiently the corresponding trimethylsilyl ethers. This system discriminates absolutely amines and thiols from alcohols.     

可重复使用的丙磺酸功能化纳米结构SBA-15上醇和酚与六甲基二硅氮烷的硅烷化反应(英文)

Various alcohols and phenols were trimethylsilylated in excellent yields using hexamethyldisilazane in the presence of catalytic amounts of environmentally friendly, hydrophobic, highly thermal stable, and completely heterogeneous sulfonic acid functionalized mesostructured SBA-15 in dichloromethane at ambient temperature. Primary, bulky secondary, tertiary, and phenolic hydroxyl functional groups were transformed to the corresponding trimethylsilyl ethers in excellent yields. The simple experimental procedure was accompanied by easy recovery and the catalyst was reusable (at least 18 reaction cycles); these are attractive features of this protocol.     

Selective Silylation of Alcohols,Phenols and Oximes Using N‐Chlorosaccharin as an Efficient Catalyst under Mild and Solvent‐Free Conditions

Efficient silylation of OH group in alcohols, phenols and oximes is described using a catalytic amount of N‐chlorosaccharin and hexamethyldisilazane (HMDS) under mild and solvent‐free conditions. This silylation reaction can be carried out with excellent and interesting various selectivities.     

Alumina Sulfuric Acid as an Efficient and Recyclable Heterogeneous Catalyst for the O-Silylation of Alcohols,Phenols, and Oximes

Alumina sulfuric acid as a recyclable catalyst conducts the transformation of various types of alcohol, phenols, and oximes with hexamethyldisilazane (HMDS) to the corresponding O-trimethylsilylated compounds in good to excellent yields under mild and ambient conditions with short reaction times. The method is highly selective for the conversion of primary alcohols in the presence of secondary and tertiary alcohols. Additionally, the catalyst can be easily recovered and reused at least eight times without detectable loss of reactivity.     

N‐Bromosuccinimide (NBS): A Mild and Efficient Catalyst for Tetrahydropyranylation of Alcohols and Phenols under Solvent‐Free Conditions

Different types of alcohols and phenols are tetrahydropyranylated in the presence of NBS catalyst in good to excellent yields under mild, neutral and solvent‐free conditions.     

Melamine Trisulfonic Acid (MTSA): A New Efficient Catalyst for the Chemoselective Methoxymethylation of Alcohols

Melamine trisulfonic acid, which is easily prepared by the reaction of melamine with neat chlorosulfonic acid, is able to efficiently catalyze the chemoselective methoxymethylation of alcohols with dimethoxymethane (DMM). All reactions were performed under mild and completely heterogeneous reaction conditions in good to high yields.     

三溴异氰脲酸和DABCI-Br作为高效催化剂用于羟基硅烷化

The protection and deprotection of functionalgroups are indispensable in the synthesis of polyfunc-tional compounds.In addition,several chemical con-versions and multiple sequence syntheses are often re-quired for the protection of hydroxyl groups.Thesily…     

Highly Efficient and Chemoselective Zinc‐Catalyzed Hydrosilylation of Esters under Mild Conditions

A mild and highly efficient catalytic hydrosilylation protocol for room‐temperature ester reductions has been developed using diethylzinc as the catalyst. The methodology is operationally simple, displays high functional group tolerance and provides for a facile access to a broad range of different alcohols in excellent yields.     

A Highly Efficient and Recyclable Solid Acid Catalyst for Synthesis of Spiro-oxindole Dihydroquinazolinones Under Ultrasound Irradiation

A simple,efficient and green procedure for the synthesis of spiro-oxindole dihyfroquinazolinones was developed by multi-component condensation of isatoic anhydride,aniline and isatin in the presence of a novel solid acid catalyst under ultrasound irradiation.The present environmentally benign protocol offers several advantages, such as shorter reaction time,a wide range of fimctional group tolerance,the use of an inexpensive heterogeneous catalyst,and a high yield of products via a simple experimental and work-up procedure.The mesoporous solid acid catalyst was directly prepared from phytic acid by microwave-sulfonation method without template.The phytic acid based solid acid was fully characterized by means of Fourier transform infrared spectroscopy(FTIR),Raman spectroscopy,X-ray diffraction(XRD),X-ray photoelectron spectroscopy(XPS),and transmission electron imcroscopy(TEM).The catalyst can be recovered and reused for at least five runs without significant impact on the product yields.     

An Efficient Method for Sulfonylation of Amines,Alcohols and Phenols with N-Fluorobenzenesulfonimide Under Mild Conditions

A new and convenient procedure was developed for the preparation of sulfonamides and sulfonic esters using N-fluorobenzenesulfonimide(NFSI) as a novel phenylsulfonyl group transfer reagent. In this protocol, a broad range of functional groups were tolerated to give the corresponding sulfonamides or sulfonic esters in moderate to excellent yields. The synthetic strategy for sulfonamides formation proceeded efficiently even under base-, metal-and additive-free conditions with the advantages of operational simplicity, mild reaction conditions as well as short reaction time.     

Efficient,Rapid, and Regioselective Bromination of Phenols and Anilines with N-Bromosaccharin Using Tungstophosphoric Acid as a Heterogeneous Recyclable Catalyst

A simple, efficient, and rapid method for high-yielding regioselective mono bromination of phenols and anilines has been achieved by treatment with N-bromasaccharin in the presence of a catalytic amount of tungstophosphoric acid.     

Sulfonated Charcoal,a Mild and Efficient Reagent for the Tetrahydropyranylation of Alcohols and Phenols

Sulfonated charcoal has been demonstradted to be very effective and mild catalyst for the tetrahydropyranylation of alcohols and phenols.     

A Mild and Efficient Method for Tetrahydropyranylation/Depyranylation of Alcohols and Phenols Under Neutral Conditions

Alcohols and phenols are tetrahydropyranylated rapidly in high yields in the presence of lithium bromide and dichloromethane at room temperature. Deprotection of these THP ethers can also be effected readily by mere change of the solvent to methanol and refluxing with excess lithium bromide. Due to neutral reaction conditions employed, the method is also compatible with compounds having acid sensitive functional groups.     

CuO‐CeO2 Nanocomposite: A Highly Efficient Recyclable Catalyst for the Green Synthesis of 1,8‐Dioxooctahydroxanthenes in Water

CuO‐CeO₂ nanocomposite is reported as a highly efficient and recyclable catalyst for the green synthesis of 1,8‐dioxooctahydroxanthenes in water. This catalyst can be recovered by simple filtration and recycled up to 8 consecutive runs without any losing of its efficiency.     

Xanthan Sulfuric Acid: An Efficient and Recyclable Solid Acid Catalyst for Pechmann Condensation

In this report, substituted coumarins are formed via Pechmann condensation using various substituted phenols and ethyl acetoacetates in the presence of xanthan sulfuric acid as a solid acid catalyst under solvent-free conditions. This method is very simple, cost-effective, and has shorter reaction times, and the catalyst could be reused.     

Natural Kaolinitic Clay: A Mild and Efficient Catalyst for the Tetrahydropyranylation and Trimethylsilylation of Alcohols

Natural kaolinitic clay possessing transition metals such as Fe, Ti in its lattice has been found to catalyze efficiently the protection of a variety of alcohols with 2,3-dihydro-4H-pyran (DHP) and hexamethyldisilazane (HMDS) at ambient conditions.     

用于烯烃二羟化反应的一种经济，高效且可重复使用的催化体系

以价廉的3,6-二氯哒嗪和奎宁为原料,通过两步反应即可得到一种可重复使用的金鸡纳生物碱衍生物配体。以NMO为辅助氧化剂在丙酮－水体系中，将此配体用于七种烯烃的不对称二羟化反应。反应结束后，用乙醚将产品从催化体系中萃取出来，得到80%~93%的产率和51%~99%的对映体过量值。以反式－二苯乙烯为底物进行催化体系的重复使用试验。循环使用十次，得到88%~92%的产率和>99%的对映体过量值。     

Chloroferrate(III) Ionic Liquid as Recyclable Catalyst for the Acetylation of Alcohols and Phenols and for 1,1‐Diacylation of Aldehydes

A Lewis acidic ionic liquid, [bmim][FeCl₄], was employed to catalyze acetylation of alcohols and phenols, and the conversion of aldehydes to corresponding 1,1‐diacetates without conventional organic solvents. The catalyst is easily available, water‐tolerant, recoverable and easy to handle.