Oxidations methanesulfonic anhydride

Other useful dehydrating agents are dimethylaminosulfur trifluoride (DAST), methyl A -(triethylammoniosulfonyl)carbamate (Burgess salt), acetic anhydride, oxalyl chloride, and phosphorous oxychloride, each one in combination with triethylamine (89). Dehydration of O-sUylated hydroxamic acids using trifluoro-methanesulfonic anhydride and triethylamine under mild conditions also gave nitrile oxides, which in the presence of olefins led to the formation of 2-isoxazolines in moderate to good yields (90). In view of the less readily available starting materials, this method probably will be of limited use. 

OXIDATIVE LACTONIZATION Dimethyl sulfoxide-Methanesulfonic anhydride. Lead tetraacetate. 

Oxidative laetonization. A recently discovered group of mycotoxins known as tryptoquivalineS has a novel spirolactone unit derived from N-acyltryptophans. A typical member of the group, tryptoquivaline G (1), has now been synthesized by Biichi and co-workers and has been shown to be derived from D-tryptophan. A key step involves oxidation of a derivative (2) of L-tryptophan with DMSO and methanesulfonic anhydride (2 equiv.) to 3 and 4. NBS has been used for such a reaction, but it can also effect undesired nuclear bromination. The main product 3 was converted in several steps into tryptoquivaline L, the C,9 epimer of 1. Contra-thermodynamic epimerization (KH, then protonation) converted this isomer into 1 and thus proved the absolute configuration. 

NaHCOs, and methanesulfonic anhydride.Dimethyl sulfoxide in 48% HBr oxidizes benzylic alcohols the aryl aldehydes.Note that Swern oxidation of molecules having alcohol moieties, as well as a disulfide, leads to the ketone without oxidation of the sulfur. Sulfoxides other than DMSO can be used in conjunction with oxalyl chloride for the oxidation of alcohols,including fluorinated sulfoxides and a polymer-bound sulfoxide. ... 

Related Reagents. iV-Chlorosuccinimide-Dimethyl Sulfide Chromic Acid Dimethyl Sulfide-Chlorine Dimethyl Sulfoxide-Acetic Anhydride Dimethyl Sulfoxide-Dicyclohexylcarbo-diimide Dimethyl Sulfoxide-Methanesulfonic Anhydride Dimethyl Sulfoxide-Oxalyl Chloride Dimethyl Sulfoxide-Sulfur Trioxide/Pyridine Dimethyl Sulfoxide-Trifluoroacetic Anhydride Dimethyl Sulfoxide-Triphosgene Manganese Dioxide Pyridinium Chlorochromate Pyridinium Dichromate Ruthenium(IV) Oxide Silver(I) Carbonate on Celite 1,1,1-Triacetoxy-1,1-dihydro-1,2-benziodoxol-3( l/ -one. 

Oxidation of Alcohols. Primary and secondary alcohols can be oxidized to aldehydes and ketones in good yields via treatment with methanesulfonic anhydride and dimethyl sulfoxide in HMPA (eqs 8 and 9). Dichloromethane can be substituted as the solvent, but the use of HMPA leads to cleaner products. Methanesulfonic anhydride works especially weU for the conversion of primary alcohols to aldehydes. Benzylic aldehydes can also be formed using this method. 

Isoindoles can be produced by eliminations from A-substituted isoindolines (1,3-dihydro-isoindoles), themselves readily produced by the reaction of a nitrogen nucleophile and a l,2-bis(bromomethyl)-benzene examples are the pyrolytic eUmination of acetic acid from the cyclic hydroxylamine acetate,or, at a much lower temperature, of benzyl alcohol from an A-hydroxy-isoindoline benzyl ether, or of methanesulfonic acid from a corresponding mesylate. A-substituted isoindoles, too, have generally been made from an isoindoline by elimination processes, thus A-oxides can be made to lose water by pyrolysis," or better, by treatment with acetic anhydride. ... 

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