Silver oxide, reaction with boron

Methyl cc-D-glucofuranosidurono-6,3-lactone (26) may be obtained exclusively by reaction of 4 with trimethyl orthoformate in the presence of boron trifluoride etherate.28 Its 2,5-dimethyl ether (27) is formed by methyl iodide-silver oxide methylation29,30 (Purdie-Ir-... 

The value of methylation studies in structural determination of carbohydrates is well known. Methylation of sucrose has generally been achieved by the use of dimethyl sulfate-sodium hydroxide,34,35 methyl iodide-silver oxide-acetone,20 sodium hydride-methyl io-dide-N,N-dimethylformamide,35 or diazomethane-boron trifluoride etherate.36,37 The last method (already applied to monosaccharides38,39) has been found particularly useful for sucrose, because it proceeds without concomitant migration of acyl groups. The reaction of 2,3,6,T,3, 4, 6 -hepta-0-acetylsucrose (21) and 2,3,4,6,1, 3, 4 -hepta-O-acetylsucrose (22) with diazomethane in dichloromethane in the presence of a catalytic proportion of boron trifluoride etherate for 0.5 h at —5° gave the corresponding 4-methyl (23) and 6 -methyl (24)... 

The synthesis of medicinally relevant 4-substituted 2(5//)-furanones has been achieved by a coupling reaction of the triflate derived from p-tetronic acid with alkyl-and cyclopropylboronic acids (Scheme 10.8).22 This reaction was mediated by bis(acetonitrile)dichloropalladium and silver oxide. Interestingly, optically active cyclopropyl boronic acids were not racemized during this coupling reaction. 

In 2006, Yu et al. combined pyridinyl-directed C-H activation and C-C bond formation with alkylboronic acids (see Section 10.5.4.2).23 The success of this transformation relied on the combination of palladium acetate (10 mol%), benzoquinone (1 equiv), and silver oxide or carbonate (0.5 equiv) in a protic solvent, but an excess of boronic acid (3 equiv) was required (Scheme 10.9). Interestingly, in this reaction silver oxide played a dual role as promoter for the transmetallation step and as cooxidant with benzoquinone. 

In 2007, Wu et al. showed that arylboronic acids and the corresponding boronates reacted with terminal alkynes in the presence of a palladacycle as catalyst and silver oxide (Scheme 10.80).132 As in the Mori reaction using basic silver salts, stoichiometric amounts of silver ion were required for high efficiency. 

Very dangerous fire hazard by spontaneous chemical reaction. Moderately explosive when exposed to flame. Explosive reaction with dichlorine oxide, silver nitrate, concentrated nitric acid, nitrogen trichloride, oxygen. Reacts with mercury(II) nitrate to form an explosive product. Ignition or violent reaction with air, boron trichloride, Br2, CI2, aqueous halogen solutions, iodine, metal nitrates, NO, NCI3, NO3, N2O,... 

PnparatioH. A procedure described by Meerwein et al. involving reaction of boron trifluorldt thorite with i luiponiion of silver oxide in nitromethine li... 

METHYL SULFOXIDE (67-68-5) CjHjOS (CHjIjSO Combustible liquid [explosion limits in air (vol %) 2.6 to 63.0 flashpoint 203°F/95°C oc autoignition temp 419°F/215°C Fire Rating 2]. Violent or explosive reaction with strong oxidizers, acryl halides, aryl halides and related compounds, alkali metals p-bromobenzoyl acetanilide, boron compounds, especially hydrides iodine pentafluoride, magnesium perchlorate, methyl bromide, perchloric acid, periodic acid, silver fluoride, sodium... 

SILVER FLUORIDE or SILVER(I) FLUORIDE or SILVER MONOFLUORIDE (7775-41-9) AgF AgF HOH Moisture- and light-sensitive, hygroscopic, corrosive solid. Contact with acetylene produces silver acetylide, a shock-sensitive explosive material. Contact with ammonia produces conpounds that are explosive when dry. Contact with hydrogen peroxide causes violent deconposition and release of oxygen gas. Contact with boron, strong oxidizers may cause fire and explosions. Violent reaction when mixed with calcium hydride (fiiction sensitive) dimethyl sulfoxide (DMSO) silicon. Soluble silver compounds attack some forms of plastics, rubber, and coatings. 

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