Ethers, Acetals, and Alcohols

2-Methylglycidic acid is regio- and stereoselectively reduced to 2-deutero-3-hydroxybutanoic acid by NaBD4-DO in DjO [MV3], while in the presence of LiBr the regioselectivity is lower. F-Alkyl-a,p-epoxyesters are also reduced to diols by NaBH4 in alcoholic media [LPl]. 

Oxetanes are also reduced by aluminohydrides [SP2]. When 2-substituted by an aryl group, the Lewis acidity of the reagent and the electronic character of the aryl substituent determined the relative amounts of primary and secondary alcohols so formed [BL5, SS8]. 

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Iron(III) bromide [10031-26-2], FeBr, is obtained by reaction of iron or inon(II) bromide with bromine at 170—200°C. The material is purified by sublimation ia a bromine atmosphere. The stmcture of inoa(III) bromide is analogous to that of inon(III) chloride. FeBr is less stable thermally than FeCl, as would be expected from the observation that Br is a stronger reductant than CF. Dissociation to inon(II) bromide and bromine is complete at ca 200°C. The hygroscopic, dark red, rhombic crystals of inon(III) bromide are readily soluble ia water, alcohol, ether, and acetic acid and are slightly soluble ia Hquid ammonia. Several hydrated species and a large number of adducts are known. Solutions of inon(III) bromide decompose to inon(II) bromide and bromine on boiling. Iron(III) bromide is used as a catalyst for the bromination of aromatic compounds. 

Properties.—Colourless liquid, with an agreeable fruity smell b. p. 77° sp. gr. o 9o68 at 15° soluble in about 11 parts of water miscible in all pioportions with alcohol, ether, and acetic acid. 

The model procedure described above is applicable to allylic alcohols, ethers, and acetates. The submitters results for the conversion of several such compounds to the corresponding olefins, performed on a smaller... 

Oxygen functionalities, such as alcohols, ethers, and acetate groups, and halogens at the allylic position, deshield when the fluorine is at the terminal position and shield when it is at the internal 2-position (Scheme 3.43). 

The presence of ionic species is demonstrated by the conductivity of the solutions. It is a strongly acidic solvent that protonates alcohols, ethers, and acetic acid. These substances are not normally bases, but they have an unshared pair of electrons that can function as a proton acceptors. 

Styphnic acid is a yellow crystalline solid with a melting point of 176 Celsius. It is insoluble in water, but soluble in alcohol, ether, and acetic acid. Styphnic acid turns deep yellow on contact with air, so it should be stored in tightly sealed bottles in a cool place. The compound is corrosive and readily forms salts with metal hydroxides and carbonates—many of which are primary explosives, i.e., lead styphnate. Styphnic acid bums rapidly and violently when ignited. For safety reasons, styphnic acid should be stored wet with 10% water. It is used primarily in the manufacture of lead styphnate, but is used with outstanding results in explosives compositions when mixed with nitrocellulose, sodium nitrate, or ammonium perchlorate and... 

Hazards Use care when handling 30% hydrogen peroxide. Keep it away from alcohol, ethers, and acetates to avoid formation of dangerous peroxides. Use the standard warnings when using concentrated sulfuricacid. Acetone is flammable so avoid contact with flames, sparks, and other sources of ignition. 

Homologation of acetylenes to allenes. A one-pot homologation of acetylenes to allenes involves reaction of an acetylenic compound with formaldehyde (1.6 equiv.), diisopropyl amine (1.2 equiv.), and copper(l) bromide at reflux in dioxane or THF (equation I). Other amines and metal salts can be employed, but diisopropylamine and copper(I) bromide give the most satisfactory results (26-97% yields). The reaction is general only for terminal acetylenes and is successful with propargylic alcohols, ethers, and acetates. Racemization is not observed with optically active... 

Properties Colorless, mobile, strongly refractive liquid strong odor. D 1.0830 (20/20C), bp 139.9C, fp —73.1C, flash p 121F (49.4C) (CC), autoign temp 732F (385C), wt/gal 9.01 lb (20C). Miscible with alcohol, ether, and acetic acid soluble in cold water decomposes in hot water to form acetic acid. Combustible. 

After this early work in setting up the optimum reaction conditions, a further, more detailed, study of catalyst structure was instigated. A range of dihydroisoquinolinium salts containing alcohol, ether and acetal functionalities was tested [24]. 

PHYSICAL PROPERTIES colorless liquid fruity, pleasant odor soluble in alcohol, ether and acetic acid practically insoluble in water MP (unknown) BP (98°C, 208 F) DN (0.8665 g/mL at 20°C) LSG (0.87) VD (unknown) BP (unknown). 

It forms small, white, transparent, friable crystals has an odor which recalls at the same time those of laurel camphor and of pepper has a hot taste is insoluble in water, readily soluble in alcohol, ether and [acetic acid fuses at IGS" (388°.4 P.), boils at 312 (413 .6P.). 

Olefins from Allylic Alcohols, Ethers, and Acetates ... 

Scheme 2.90 Titanium-catalysed DKRs of alcohols, ethers and acetals.

The Nicholas reaction enables efficient substitution reactions of propargyl alcohols, ethers, and acetates. Prior to the substitution step, dicobalt octacarbonyl reacts with the alkyne to yield cobalt-alkyne complex 1. The resulting organometallic complex reacts with inter- or intramolecular nucleophiles in the presence of a Lewis or protic acid to furnish desired substitution products 2. The cobalt-complexed alkyne can be oxidatively removed after this step or used to further fiinctionalize the Nicholas reaction products. The stereoselective synthesis of chiral products using the title reaction is also possible. ... 

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