Acetals and ketals are readily deprotected under neutral conditions in the presence of acetone and catalytic amounts of indium(III) trifluoromethanesulfonate (<0.8 mol %) at room temperature or mild microwave heating conditions to give the corresponding aldehydes and ketones in good to excellent yields.
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http://dx.doi.org/10.1021/jo0707075 | DOI Listing |
J Org Chem
March 2016
Department of Chemistry & Chemical Biology, Rutgers The State University of New Jersey, 610 Taylor Road, Piscataway, New Jersey 08854, United States.
Nucleoside O-glycosylation represents an archetypal problem in chemical selectivity, inasmuch as the nucleobase (an undesired site of reaction) is usually more nucleophilic than the hydroxyl (the desired site of reaction). Optimized reaction conditions have been developed for the efficient O-glycosylation of nucleoside hydroxyls. Both thioglycoside and Schmidt imidate donors (1.
View Article and Find Full Text PDFOrg Biomol Chem
January 2014
School of Chemistry, Bharathidasan University, Tiruchirapalli 620 024, Tamil Nadu, India.
Indium(III) triflate is found to be an effective catalyst for the benzannulation reactions of o-alkynylbenzaldehydes with enolisable aldehydes, ketones, 1,3-diketones and β-keto esters. The reactions produce naphthyl ketones through ring opening of adducts arising from the inverse electron demand Diels-Alder reactions between in situ generated isochromenylium cations and enols. The main feature of the method is selective formation of naphthyl ketones in a highly regioselective manner without any decarbonylation.
View Article and Find Full Text PDFChem Pharm Bull (Tokyo)
February 2014
Laboratory of Medicinal Chemistry, Faculty of Pharmacy, Takasaki University of Health and Welfare, 60 Nakaorui, Takasaki, Gunma 370–0033, Japan.
An oxidative methyl esterification of aldehydes was effectively achieved. The trivalent indium reagent, indium(III) triflate, was revealed to accelerate the reactions in many cases. Aromatic aldehydes with various substituents were subjected to this method, and each produced the corresponding methyl esters in good to excellent yields within a relatively short reaction time.
View Article and Find Full Text PDFJ Org Chem
January 2012
Department of Chemistry and Biochemistry, University of California, Santa Cruz, 1156 High Street, Santa Cruz, California 95064, USA.
We report a simple, efficient, and general method for the indium-mediated enantioselective propargylation of aromatic and aliphatic aldehydes under Barbier-type conditions in a one-pot synthesis affording the corresponding chiral alcohol products in very good yield (up to 90%) and enantiomeric excess (up to 95%). The extension of this methodology to ketones demonstrated the need for electrophilic ketones more reactive than acetophenone as the reaction would not proceed with just acetophenone. Using the Lewis acid indium triflate [In(OTf)(3)] induced regioselective formation of the corresponding homoallenic alcohol product from acetophenone.
View Article and Find Full Text PDFChem Pharm Bull (Tokyo)
October 2009
Laboratory of Medicinal Chemistry, Faculty of Pharmacy, Takasaki University of Health and Welfare, Takasaki, Gunma 370-0033, Japan.
A convergent one-step transformation of tetrahydropyranyl (THP) ethers is described. According to our earlier experiments, indium(III) triflate has proven to be an efficient catalyst for the transformation of THP ethers into their corresponding acetates. In further intensive work, we have developed a useful transforming reaction of THP ethers using various anhydride moieties.
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