Simple and Highly Efficient Method for the Deprotection of Allyl Ethers Using Dimethylsulfoxide–Sodium Iodide

A simple and highly efficient method for deprotection of allyl ethers has been developed using dimethylsulfoxide–sodium iodide (catalytic amount). This method is inexpensive, has simple reaction conditions, has an easy workup procedure, proceduces excellent yields (60–99%), and is effective for several structurally varied allyl ethers.     

Facile and Highly Selective Deprotection of tert‐Butyldimethyl Silyl Ethers using Sulfated SnO2 as a Solid Catalyst

Highly selective deprotection of tert‐butyldimethylsilyl ethers at room temperature has been described using sulfated SnO₂ as an efficient solid catalyst.     

Triton B–Mediated Mild,Convenient, and Efficient Method for the Selective Alkylation of Cyclic Secondary Amines and Thiols

Alkylation of cyclic secondary amines, thiols, and pyridazinones has been demonstrated with alkyl halides using Triton B as base and reaction medium.     

A Convenient and Efficient Procedure for Oxime Ethers

In connection with our asymmetric reduction research, we are of interest to synthesize ketoxime ethers because they give good enantioselectivty in the reduction system of Lewis acid-NaBH4-Ligand1. In the literature the oxime ethers were made under anhydrous conditions using strong base such as NaH or sodium alkoxides to realize the substitution reaction between alkyl halide and oxime2. The reaction has also been performed under PTC conditions3. There were cases where the yields were low…     

Selective Deprotection of tert -Butyldimethylsilyl Ethers Using Nafion-H®/Sodium Iodide (or Bromodimethylsulfonium Bromide) in Methanol

Abstract

Catalytic amounts of bromodimethyl sulfonium bromide, or Nafion-H along with NaI (1 equiv.), in methanol cleave a variety of TBDMS ethers readily in high yields. Alkyl TBDMS ethers react more readily and selectively compared to phenolic TBDMS ethers, benzyl, and methyl ethers.     

A General and Efficient Protocol for the Synthesis of Biaryl Ethers from Aryl Silyl Ethers Using Cs2CO3

Biary ethers are known to be important organic compounds for their biological interests and great presence in life science industries. A number of them have consequently provide a strong incentive for synthesis, which includes the classical Ullman reaction, metal-catalyzed substitution, SN-Ar based type, intramolecular oxidative coupling and MW-assisted methods. Although the above synthetic strategies are particularly important, a method is required for the direct conversion of phenoxy silane to biaryl ethers without recourse to hydrolytic conditions.     

Mild and Efficient Method for α-Thiocyanation of Ketones and β-Dicarbonyl Compounds Using Bromodimethylsulfonium Bromide–Ammonium Thiocyanate

An efficient and convenient method for α-thiocyanation of ketones and β-dicarbonyl compounds has been developed using a reagent combination of bromodimethylsulfonium bromide (BDMS) and ammonium thiocyanate in acetonitrile. The developed method is mild and gave good yield of the products at room temperature.     

Decorating Channel Walls in Metal–Organic Frameworks with Crown Ethers for Efficient and Selective Separation of Radioactive Strontium(II)

Nuclear accidents and the improper disposal of nuclear wastes have led to serious environmental radioactive pollutions. The rational design of adsorbents for the highly efficient separation of strontium(II) is essential in treating nuclear waste and recovering radioactive strontium resources. Metal–organic frameworks (MOFs) are potential materials for the separation of aqueous metal ions owing to their designable structure and tunable functionality. Herein, a novel 3D MOF material MOF-18Cr6, in which 1D channels are formed using 18-crown-6-ether-containing ligands as channel walls, is fabricated for strontium(II) separation. In contrast to traditional MOFs designed by grafting functional groups in the framework pores, MOF-18Cr6 possesses regular 18-crown-6-ether cavities on the channel walls, which not only can transport and intake strontium(II) via the channels, but also prevent blockage of the channels after the binding of strontium(II). Consequently, the functional sites are fully utilized to achieve a high strontium(II) removal rate of 99.73 % in simulated nuclear wastewater. This study fabricates a highly promising adsorbent for the separation of aqueous radioactive strontium(II), and more importantly, can provide a new strategy for the rational design of high-performance MOF adsorbents for separating target substances from complex aqueous environments.     

Convenient and Efficient Method for the Obtainment of Ketones from Highly Hindered Aromatic N,N‐Dimethyl‐amides

A simple and efficient procedure to synthesize highly hindered alkyl aryl ketones that involves the coupling of N,N‐dimethyl‐3,5‐di‐tert‐butylsalicylamide with organolithium compounds is described. Mild reaction conditions and good to excellent yields of the products are the noteworthy advantages of the procedure.     

TiCl4, Dioxane—A Facile and Efficient System for De-O-Benzylation,De-O-Allylation,and De-O-Xylylation of Phenolic Ethers

Abstract

Simultaneous de-O-xylylation and reductive coupling was observed when 1 equiv. of the dialdehyde 2a/2b was treated with 5 equiv. of each TiCl₄ and Zinc which lead to the development of TiCl₄ in dioxane as a new system for the facile deprotection of phenolic ethers 4a–4d, 5a–5d, and 6a–6c.     

An Alternative Method for the Highly Selective Iodination of Alcohols Using a CsI/BF3·Et2O System

Abstract

A variety of allylic and benzylic alcohols have been converted into the corresponding iodides using cesium iodide (CsI) in the presence of boron trifluoride etherate (BF₃·Et₂O) in acetonitrile under mild conditions.     

Molecular Designs and Properties of Highly Efficient Blue Emitters for OLEDs

Advances made in the molecular design of modern optoelectronic materials have made significant contributions toward the development of organic electronics. The organic light-emitting devices (OLEDs) employing monodisperse or polymeric conjugated materials possess the most promising prospects. However, materials suitable for long-term use as blue light emitters are still far from optimization in terms of stability. In the past few years, interesting materials based on 9,9-diaryl-substituted f…     

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.     

DABCO–Bromine Complex: A Novel Oxidizing Agent for Oxidative Deprotection of THP and Silyl Ethers and Semicarbazones to Corresponding Carbonyl Compounds

A tetrameric DABCO–bromine complex was synthesized, characterized, and utilized as a novel active bromine complex for the oxidative deprotection of THP and silyl ethers and semicarbazones to carbonyl compounds.     

A Mild and Highly Efficient Catalyst for Beckmann Rearrangement, BF3·OEt2

BF₃·OEt₂ (Boron trifluoride etherate), an inexpensive and commercially easily available Lewis acid stoichiometrically employed for Beckamann rearrangement in general, was now found to efficiently catalyze Beckmann rearrangement of ketoximes into their corresponding amides (up to 99% yield) in anhydrous acetonitrile under reflux temperature.     

An Efficient and Convenient Cyclization Method for the Synthesis of Flavans

Flavansrefertoalargegroupofnaturallyoccurringcompoundspossessinga2-phenyl-chromannucleus.Naturallyoccurringflavansexhibitanumberofimportantbiologicalactivitieswhichifexploitedproperly,mayleadtovaluablenewdrugsoragrochemicals'.Inflavansynthesis,thekeystepistoconstructthe3,4-dihydrobenzopyranring-Variousmethodshavebeendevelopedfortheringformation,butmostoftheminvolvemultiplestepsandgivelowoverallyields2.Inthispaper,BF3wasusedforthefirsttimeasanefficientcatalysttoformthepyranringfroml,3-diaryIp…     

A Facile and Efficient synthesis for A Series of Bis(N-imidazolylethyl) Ethers

Multi-dentateligandssuchasopen-chainandcycliccrownethershavereceivedextensiveintCrestsandbeenmuchstudiedinhost-guestinteraction,supramolecularandbioorganicchemistry".Asabindingand/orcatalyticsiteintheactivecenterofmetalloenzymesandnon-metalloenzymes,imidazoleplaysaveryimportantroleinbiologicalsystem.Imidazole-basedbiomimeticmodelsandmacrocycles,especiallyrecentimidazoliumcyclophaneshavebeenpaidincreasingattention5-ll.Inspiteofthis,onlyoneliteratUre,toourknowledge,reportedthesynthesisofbis(N-i…     

Efficient and Convenient Deprotection of Thiocarbonyl to Carbonyl Compounds Using 3-Carboxypyridinium and 2,2′-Bipyridinium Chlorochromates in Solution,Dry Media,and under Microwave Irradiation

Summary. A synthetic utility of 3-carboxypyridinium (CPCC) and 2,2-bipyridinium (BPCC) chlorochromates in deprotection reactions is reported. Different types of thioamides, thioureas, thiono esters, and thioketones are deprotected to their corresponding carbonyl compounds with these reagents in good to excellent yields. The reactions were carried out in solution, under solvent-free conditions, and under microwave irradiation. The results show that with both reagents the rates of the reactions and the yields are usually highest under microwave irradiation.     

An Efficient and Chemoselective Deprotection of tert-Butyldimethyl- silyl Protected Alcohols Using SnCl2.2H2O as Catalyst

An efficient and selective method for the deprotection of primary alcoholic tert-butyl-dimethylsilyl (TBS) ethers using SnC12“2H20 as catalyst is described. The reaction conditions allow primary alcoholic TBS ethers to be desilylated chemoselectively in the presence of phenolic TBS ethers, secondary and tertiary alcolholic TBS ethers, and the extensively used TBDPS-, acetyl-, benzyloxycarbonyl-, p-toluenesulfonyl- and benzyl protective groups.     

Reduction and Reductive Alkylation of α-tert-Butylthio Carbonyl Compounds. An Efficient Method for Stepwise α-Alkylation of Esters,Nitriles and Ketones Via the α-Tert-Butylthio Derivatives

An efficient and generally applicable method for stepwise α-alkylatton of esters, nitriles, and ketones via the α-tert-butylthio derivatives is described. The method involves reductive-protonation and reductive-alkylation of α-alkylthio α,α-bis-alkylated carbonyl compounds which are prepared by stepwise alkylation of the corresponding simple α-alkylthio carbonyl precursors. The reduction is conveniently performed by use of stoichiometric amounts of a dissolving metal, particularly lithium, affording correspondingly the α-mono-and the α,α-bis-alkylated carbonyl compounds in good yields.