Butyldimethylsilyl Ethers Research Articles

HF–Pyridine: A Versatile Promoter for Monoacylation/Sulfonylation of Phenolic Diols and for Direct Conversion of t-Butyldimethylsilyl Ethers to the Corresponding Acetates

Abstract Monoacylation and trifluoromethanesulfonylation of phenolic diols were achieved by the aid of HF–pyridine, whereas diacylation occurred with pyridine alone. Furthermore, HF–pyridine was found to promote the direct conversion of t-butyldimethylsilyl ethers to the corresponding acetates.

Stereoselective synthesis of key intermediates for the preparation of strobilurins

The highly stereoselective synthesis of benzyl and tert -butyldimethylsilyl ethers of 3-methyl-6-arylhexa-3( Z ),5( E )-dienols, which are key intermediates in the syntheses of strobilurins A and X, has been developed.

A Mild and Efficient Desilylation of O-tert-Butyldimethylsilyl Ethers Mediated by Chlorotrimethylsilane and Potassium Fluoride Dihydrate in Acetonitrile

Desilylation of O-tert-butyldimethylsilyl ethers was achieved by a reagent system consisting of chlorotrimethylsilane and potassium fluoride dihydrate in acetonitrile. This alternative desilylation procedure is chemoselective, generally effective and operationally simple, and should find practical applications in ­organic synthesis.

Regio‐ and Stereoselective Synthesis of Z‐Vinylic Tellurides from Propargylic Alcohols: A Route to Chiral Z‐Enynes.

AbstractFor Abstract see ChemInform Abstract in Full Text.

A Facile, Catalytic, and Environmentally Benign Method for Selective Deprotection of tert-Butyldimethylsilyl Ether Mediated by Phosphomolybdic Acid Supported on Silica Gel

An environmentally benign PMA supported on SiO(2) is found to be an efficient catalyst for the chemoselective deprotection of TBDMS ethers under very mild conditions. Various labile functional groups such as isopropylidene acetal, OTBDPS, OTHP, Oallyl, OBn, alkene, alkyne, OAc, OBz, N-Boc, N-Cbz, N-Fmoc, mesylate, and azide are found to be stable under the reaction conditions. This "truly catalytic" heterogeneous reaction does not require aqueous workup, and the supported catalyst and the solvent can be readily recovered and recycled.

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

AbstractFor Abstract see ChemInform Abstract in Full Text.

Aluminum Chloride (Alcl3) Promotes Selective Oxidative Deprotection of Benzylic Trimethylsilyl and Tert- Butyldimethylsilyl Ethers to the Corresponding Carbonyl Compounds with Manganese Dioxide (Mno2)

Various types of trimethylsilyl and tert-butyldimethylsilyl ethers of primary and secondary benzylic alcohols could be selectively converted to their corresponding carbonyl compounds with MnO2 in the presence of AlCl3 in good to excellent yields.

A Mild, Efficient, Inexpensive, and Selective Cleavage of Primary tert-Butyldimethylsilyl Ethers by Oxone in Aqueous Methanol

The use of a 50% aqueous methonolic solution of Oxone is described for the selective cleavage of primary tert-butyldimethylsilyl and aryl ethers at room temperature. This method enables one to deprotect tert-butyldimethylsilyl ethers of primary alcohols in the presence of tert-butyldimethylsilyl ethers of secondary and tertiary alcohols and phenols. The silyl ethers of phenols were deprotected at longer reaction times.

Iodine and its Interhalogen Compounds: Versatile Reagents in Carbohydrate Chemistry IX. A Mild and Selective Deprotection of tert-Butyldimethylsilyl (TBDMS) Ethers in the Presence of Various Protecting Groups Using Iodine Monobromide

Iodine and its Interhalogen Compounds: Versatile Reagents in Carbohydrate Chemistry IX. A Mild and Selective Deprotection of <i>tert</i>-Butyldimethylsilyl (TBDMS) Ethers in the Presence of Various Protecting Groups Using Iodine Monobromide

Direct Oxidation of Primarytert-Butyldimethylsilyl Ethers to Carboxylic Acids with Jones Reagent

Abstract Treatment of the tert-butyldimethylsilyl ethers 1a-f with Jones reagent gave the carboxylic acids 2a-f in excellent yield in the absence of potassium fluoride.

ChemInform Abstract: A Simple and Highly Chemoselective Desilylation of tert‐ Butyldimethylsilyl Ethers.

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ChemInform Abstract: Selective Acidic Cleavage of Ketals in the Presence of tert‐ Butyldimethylsilyl Ethers.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Alumina-mediated cleavage of [formula omitted]-butyldimethylsilyl ethers

A simple method for the cleavage of t -butyldimethylsilyl ethers is described which occurs on alumina surface under solvent free conditions within 10–15 minutes. Mild heating, using microwave irradiation facilitates the procedure.

Synthesis of [3,3‐D2]4‐hydroxy‐1‐(3‐pyridyl)‐1‐butanone, an internal standard for analysis of tobacco‐specific nitrosamine hemoglobin and DNA adducts

AbstractThe synthesis of [3,3‐D2]4‐hydroxy‐1‐(3‐pyridyl)‐1‐butanone ([3,3‐D2]HPB), an internal standard for the analysis of hemoglobin and DNA adducts of tobacco‐specific nitrosamines, is reported. 3‐Pyridine carboxaldehyde was converted to 2‐(3‐pyridyl)‐1, 3‐dithiane. This was condensed with 2‐(2‐bromoethyl)‐1, 3‐dioxalane to yield 2‐[2‐(3‐pyridyl)‐1, 3‐dithiane]ethyl‐1, 3‐dioxalane. Selective hydroylsis of the aldehyde protecting group produced 4‐(1, 3‐dithian‐2‐yl)‐4‐(3‐pyridyl)‐butanal, which was then labeled with deuterium adjacent to the aldehyde carbonyl group. Reduction with LiAlH4 produced the corresponding alcohol. Removal of the dithianyl protecting group required protection of the alcohol as its t–butyldimethylsilyl ether. Treatment with AgNO3/N‐chlorosuccinimide in aqueous CH3CN produced [3,3‐D2]HPB.

An efficient synthesis of S-γ-[(4-trifluoromethyl)-phenoxy]benzenepropanamine-[1-14C] maleate, an important metabolite of fluoxetine hydrochloride

S-γ-[(4-Trifluoromethyl)phenoxy]benzenepropanamine-[1-14C] maleate has been prepared in six steps from R-(-)1-phenyl-1,2-ethanediol. The isotope was incorporated by the reaction of NaCN-[14C] with the tert. butyldimethylsilyl ether of R-(-)1-phenyl-1,2-ethane-diol 2-tosylate. Borane reduction and arylation, followed by salt formation yielded S-γ-[(4-trifluoromethyl)phenoxy]benzenepropanamine-[1-14C] maleate.

Selective desilylation of [formula omitted]-butyldimethylsilyl ethers of phenols using potassium fluoride-alumina and ultrasound

The use of potassium fluoride on basic alumina in acetonitrile with ultrasound for the selecting deprotection of tert -butyldimethylsilyl ethers of phenols is described. The method, which features a non-aqueous work-up, readily cleaves tert- butyldimethylsilyl ethers of phenols at room temperature, whereas tert -butyldimethylsilyl ethers of benzyl alcohols or 2-(trimethylsilyl)ethoxymethyl ethers of phenols are stable.

Selected ion monitoring gas chromatography/mass spectrometry of 1,2‐diacylglyceroltert‐butyldimethylsilyl ethers derived from glycerophospholipids

AbstractSelected ion monitoring was used in conjunction with gas chromatography/mass spectrometry to analyzetert‐butyldimethylsilyl ethers (tert‐BDMS) of 1,2‐diacyl‐sn‐glycerols derived from naturally occurring glycerophospholipids, including those ofEscherichia coli, soybean, egg yolks and porcine liver. First, the fatty acid composition of the unknown glycerophospholipid was determined by gasliquid chromatography (GLC) and, based on that, the fatty acids (mostly &gt;0.5 wt%) were selected for monitoring the characteristic fragmentation ions produced from the fatty acid residues of the correspondingtert‐BDMS derivatives of 1,2‐diacyl‐sn‐glycerols. Next, thetert‐BDMS derivatives were separated by GLC on a 65% methylphenylsilicone gum wall‐coated open‐tubular (WCOT) column according to the degree of unsaturation and the chain length of the fatty acid residues, and then directly introduced into the ion source of the mass spectrometer. The selected fragmentation ions, [RCO+74]+ representative of the fatty acid residues, and [M‐57]+ indicative of the molecular weight of the derivatives, were monitored simultaneously. It thus became possible to determine the molecular species of thetert‐BDMS derivatives by measuring a specific combination of two [RCO+74]+ and an [M‐57]+ ion with the same retention time on the selected ion monitoring (SIM) profile. High background noise caused by volatilization of stationary phase at high temperature was largely overcome by selected ion monitoring. However, the fragmentation ion peaks produced fromtert‐BDMS derivatives of highly unsaturated glycerophospholipids showed a distorted SIM profile, which was attributed to interaction between thetert‐BDMS derivatives and the methylphenylsilicone phase of the column. Use of a WCOT column with a more polar liquid phase is therefore recommended for the analysis of highly unsaturated molecular species.

ChemInform Abstract: Synthesis of 2‐(5′,5′‐Ethylenedioxy‐1′‐methylcyclopent‐2′‐en‐1′‐yl)ethanol, and Some 2H‐Cyclopenta(b)furan Derivatives Formed by Intramolecular Displacement Reactions.

Exchange dioxolanation of 2-methyl-2-(prop-2′-enyl)cyclopentane-1,3-done (1b) gave 3,3- ethylenedioxy-2-methyl-2-(prop-2′-enyl) cyclopentan-1-one (2) which, upon reduction and esterification , afforded the epimeric 3,3-ethylenedioxy-2-methyl-2-(prop-2′-enyl) cyclopent-1-yl benzoates (6d). Oxidative cleavage of the terminal double bond in (6d),followed by sodium borohydride reduction yielded 3,3-ethylenedioxy-2-(2'-hydroxyethyl)-2-methylcyclopent-1-yl benzoate (4b) which underwent acid- catalysed rearrangement to 6a-(2′-hydroxyethoxy)-3a- methylhexahydrocyclopenta [b]furan-4-yl benzoate (8b). Flash vacuum pyrolysis of the t- butyldimethylsilyl ether (12), derived from the hydroxy acetal (4b), afforded 3-[2′- (t- butyldimethylsilyloxy )ethyl]-4,4-ethy1enedioxy-3-methylcyclopent-1-ene (14) which upon selective cleavage of the silyl ether group gave 2-(5′,5′-ethylenedioxy-1′-methylcyclopent- 2'′en-1′-y1)ethanol (7). Reaction of the mesylate (16) of (7) with lithium bromide or iodide in tetrahydrofuran at 50-55o for several hours yielded some of the corresponding 3-(2′-haloethyl) compounds (17), but gave mainly the rearranged 6a-(2′-haloethoxy)-3a-methyl-3,3a,6,6a-tetrahydro-2H-cyclopenta[b]furans (19a) and (19b). Some related chemistry is described.

Synthesis of 2-(5',5'-Ethylenedioxy-1'-methylcyclopent-2'-en-1'-yl)ethanol, and Some 2H-Cyclopenta[b]furan Derivatives Formed by Intramolecular Displacement Reactions

Exchange dioxolanation of 2-methyl-2-(prop-2′-enyl)cyclopentane-1,3-done (1b) gave 3,3- ethylenedioxy-2-methyl-2-(prop-2′-enyl) cyclopentan-1-one (2) which, upon reduction and esterification , afforded the epimeric 3,3-ethylenedioxy-2-methyl-2-(prop-2′-enyl) cyclopent-1-yl benzoates (6d). Oxidative cleavage of the terminal double bond in (6d),followed by sodium borohydride reduction yielded 3,3-ethylenedioxy-2-(2'-hydroxyethyl)-2-methylcyclopent-1-yl benzoate (4b) which underwent acid- catalysed rearrangement to 6a-(2′-hydroxyethoxy)-3a- methylhexahydrocyclopenta [b]furan-4-yl benzoate (8b). Flash vacuum pyrolysis of the t- butyldimethylsilyl ether (12), derived from the hydroxy acetal (4b), afforded 3-[2′- (t- butyldimethylsilyloxy )ethyl]-4,4-ethy1enedioxy-3-methylcyclopent-1-ene (14) which upon selective cleavage of the silyl ether group gave 2-(5′,5′-ethylenedioxy-1′-methylcyclopent- 2'′en-1′-y1)ethanol (7). Reaction of the mesylate (16) of (7) with lithium bromide or iodide in tetrahydrofuran at 50-55� for several hours yielded some of the corresponding 3-(2′-haloethyl) compounds (17), but gave mainly the rearranged 6a-(2′-haloethoxy)-3a-methyl-3,3a,6,6a-tetrahydro-2H-cyclopenta[b]furans (19a) and (19b). Some related chemistry is described.

Selective de-protection of silyl ethers

Pyridinium p -toluenesulfonate has been found to remove t -butyldimethylsilyl ethers selectively in the presence of t -butyldiphenylsilyl ethers. This methodology should find wide applicability in complex organic synthesis.