Efficient Organic Transformations Mediated by ZrOCl2·8H2O in Water

Abstract

Operationally simple and environmentally benign methods for some organic transformations comprising reductive coupling of sulfonyl chlorides, chemoselective deoxygenation of sulfoxides, and halogenation of alcohols mediated by ZrOCl₂·8H₂O/MX in water have been developed.

GRAPHICAL ABSTRACT     

ZrOCl2 Catalysed Chemoselective Conversion of Aldehydes to geminal-Diacetates and Their Cleavage： A Mild and Efficient Method

ZrOCl2 was found to be an effective Lewis acid catalyst for the solventless chemoselective conversion of aldehydes into geminal-diacetates in high yields at room temperature. Regeneration of the aldehydes from the acetals was also achieved using the same catalyst in water. The beneficial effect of microwave irradiation on the reaction was also described. Other advantages are the very low loading of catalyst, high yields achieved even on a gram scale, and considerably shortened reaction time compared to the conventional method.     

ZrOCl2·8H2O: An Efficient Catalyst for One-Pot Synthesis of α-Amino Phosphonates Under Solvent-Free Conditions

A highly efficient protocol has been developed for the three-component reaction of an amine, an aldehyde, and diethyl phopshite catalyzed by ZrOCl₂·8H₂O, an environmentally friendly catalyst, at ambient temperature. The catalyst exhibited remarkable activity and tolerated a wide variety of functional groups, providing the desired amino phosphonates in excellent yields under solvent-free conditions. Alternatively, the reaction rate can be significantly enhanced by carrying out the reaction in a monomode microwave reactor as a promoter.     

An Efficient Method for Preparing the α-Deuterated-α,β-Unsaturated Carbonyl Compounds by Reaction of Stable Phosphonium Ylides with Carbonyl Compounds in Deuterium Oxide

Carbonyl compounds reacted with stable phosphonium ylides in D₂O to give α-deuterated-α,β-unsaturated carbonyl compounds in the same flask. The chemical yield and deuterium incorporation are excellent under our procedure. The fragile group like ozonide was compatible with our reaction condition.     

An Improved Procedure for the Conversion of Carbonyl Compounds to α,β-Unsaturated Carboxylic Acids

The two carbon homologation of aldehydes and ketones to give α,β-unsaturated carboxylic acids is often carried out via the corresponding ester using metallated phosphonate reagents² (1) (Equation I). When alkyl esters (la) are employed problems are sometimes encountered in the hydrolysis step due to acid or base sensitivity but these problems can be overcome using the silyl ester (lb)³.     

A Mild and Efficient Deprotection of Geminal Diacetates Catalyzed by FeCl3 ·6H2O in Ionic Liquid

The selective deprotection of geminal diacetates promoted by FeCl3·6H2O in the ionic liquid [bmim] [BF4] canbe efficiently achieved in good yields. The ionic liquid and the catalyst can be recycled easily and the process is car ried out under mild conditions.     

Tantalum(V) Chloride–Silica Gel: An Efficient Catalyst for Conversion of Carbonyl Compounds to 1,3‐Oxathiolanes

A variety of carbonyl compounds can be easily converted to the corresponding 1,3‐oxathiolanes in the presence of a catalytic amount of tantalum(V) chloride [TaCl₅] on silica gel in dichloromethane. Mild reaction conditions, efficiency, high yields, operational simplicity, and only 2.5 mol% of TaCl₅ catalyst are some of the major advantages of the procedure.     

CuSO4 · 5H2O: A Novel,Green, Reusable,and Environmentally Friendly Catalyst for the One-Pot,Four-Component Synthesis of β-Acetamido Carbonyl Compounds

Multicomponent reactions for the synthesis of β-acetamido carbonyl compounds have been gained considerable attention in organic synthesis. In this articles, aromatic aldehydes have been employed in a one-pot reaction with enolizable ketones, acetonitrile, benzonitrile, and acetyl chloride in the presence of copper(II) sulfate petahydrate at ambient temperature to afford the corresponding β-acetamido ketones in very good yields. New compounds are reported. The use of readily available copper(II) sulfate petahydrate as a reusable and recyclable catalyst makes this process quite simple, convenient, and environmentally friendly.     

ZrOCl2 · 8H2O as an Efficient Reagent for the Solvent‐Free Synthesis of 3,4‐Dihydropyrimidin‐2‐(1H)‐ones

ZrOCl₂ · 8H₂O, a commercially available reagent, can be used for the promotion of the synthesis of 3,4‐dihydropyrimidin‐2(1H)‐ones under solvent‐free reaction conditions. All reactions were performed at 90°C in good to high yields.     

AlCl3 · 6H2O/KI/CH3CN/H2O: An Efficient and Versatile System for Chemoselective C–O Bond Cleavage and Formation of Halides and Carbonyl Compounds from Alcohols in Hydrated Media

AlCl₃ · 6H₂O/KI/CH₃CN/H₂O, an efficient and versatile system, cleaves the C–O bonds of esters, acetals, ethers, and oxathiolanes to the corresponding acids, alcohols, and carbonyl compounds chemoselectively at 80 °C in hydrated media with good yields. This system also converts the alcohols (primary/secondary) to halides and oxidizes the alcohols (primary/secondary) to the corresponding carbonyl compounds in the presence of DMSO.     

Facile and Efficient Michael Addition of Indole to Nitroolefins Catalyzed by Zn(OAc)2 · 2H2O

The Zn(OAc)₂2H₂O-catalyed Michael addition reaction of indole to electron-deficient nitroolefins to afford the corresponding adducts in good to excellent yields with high selectivity is reported.     

Aluminium Chloride Hexahydrate (AlCl3 · 6H2O): An Efficient,Facile, Mild,And Highly Chemoselective Catalytic Deprotection of Tert-Butyldimethylsilyl (TBS) Ethers

tert-Butyldimethylsilyl (TBS) phenyl / alkyl ethers were cleaved to the corresponding efficiently parent hydroxyl compounds in good yields using catalytic amounts of AlCl₃ · 6H₂O by conventional or microwave-assisted heating in methanol or isopropanol solution. Intramolecular and competitive experiments demonstrated the chemoselective deprotection of TBS ethers in the presence of triisopropylsilyl and tert-butyldiphenylsilyl ethers.     

Protection and deprotection chemistry catalyzed by zirconium oxychloride octahydrate (ZrOCl2·8H2O)

Abstract

An efficient, chemoselective, convenient, and straightforward methodology has been developed for the protection of C=O group of aldehydes/ketones as C=N moiety of hydrazones catalyzed by ZrOCl₂·8H₂O (10 mol%) in acetonitrile and the same catalyst in methanol oxidatively cleaves C=N moiety of hydrazones to provide parent carbonyl compounds in high yields. The reactions have been performed in aerobic condition. The catalyst is inexpensive, readily available, easy to handle, insensitive to air and moisture, easily recoverable and can be reused and importantly less toxic.     

ZrOCl2 · 8H2O: An Efficient,Ecofriendly, and Recyclable Catalyst for Ultrasound-Accelerated,One-Pot,Solvent-Free Synthesis of 8-Aryl-7,8-dihydro-[1,3]dioxolo[4,5-g]quinolin-6-(5H)-one and 4-Aryl-3,4-dihydroquinolin-2(1 H)-one Derivatives

A convenient, one-pot, solvent-free reaction of amines, aromatic aldehydes, and Meldrum's acid to form 8-aryl-7,8-dihydro-[1,3]dioxolo[4,5-g]quinolin-6-(5H)-one and 4-aryl-3,4-dihydroquinolin-2-(1H)-one in the presence of 10 mol% ZrOCl₂.8H₂O under ultrasonic irradiation is described. This new protocol offers several advantages including low catalyst loading, clean reaction, easy workup, use of recyclable and ecofriendly catalyst, short reaction times, good yields, and solvent-free conditions.

Supplemental materials are available for this article. Go to the publisher's online edition of Synthetic Communications® to view the free supplemental file.     

An Efficient Method for the Synthesis of Acyl-diazenes Using NaNO_2/NaHSO_4·H_2O

Azo compounds are widely utilized as analytic reagents and dyes1, they can also be used in material of non-linear optics, material of optics information storing in laser disks, and dyes with oil solubility in photochromy in modern technology2. Recently, many noteworthy studies have shown that some azo compounds possess excellent optical memory and photoelectric properties3,4. For example, polymer scaffolds bearing azobenzene-potential are useful for optical information storage, azo-dye doped…     

Simple,Mild, and Efficient Method for the Reduction of 1,4‐Benzoquinones to Hydroquinones by the Action of NaN3

A simple, mild, and efficient method is presented for the reduction of 1,4‐benzoquinones to hydroquinones by the action of NaN₃ under neutral conditions in the presence of water.     

Mild and Efficient Debromination of vic-Dibromides to Alkenes with FeCl3·6H2O/Indium System

The FeCl₃ · 6H₂O/indium system efficiently causes debromination of various dibromides to the corresponding alkenes in good to excellent yields under mild conditions.     

Michael Additiion of Alkyl Amine to α,β-Unsaturated Carbonyl Compounds Catalyzed by KF／Al2O3

The β-aminocarboxylic acid derivatives were synthesized by Michael addition reaction ofalkyl amine and α,β-unsaturated carbonyl compounds in the presence of potassium fluoride onalumina.     

Efficient,Green, Solvent-Free Synthesis of 3,4-Dihydropyrimidin-2(1H)-ones via Biginelli Reaction Catalyzed by Cu(NO3)2·3H2O

The synthesis of 3,4-dihydropyrimidin-2-(1H)-ones derivatives via a three-component Biginelli reaction using copper nitrate as a catalyst under solventless conditions is reported, providing a green, rapid, efficient, and convenient method for the preparation of Biginelli compounds in good yields.