Alcohols reaction with diazo compounds

Alcohols react with diazo compounds to form ethers, but diazomethane and diazo ketones are most readily available, giving methyl ethers or a-keto ethers, respectively. With diazomethane " the method is expensive and requires great caution, but the conditions are mild and high yields are obtained. Diazomethane is used chiefly to methylate alcohols and phenols that are expensive or available in small amounts. Hydroxy compounds react better as their acidity increases ordinary alcohols do not react at all unless a catalyst, such as HBp4 or silica gel, is present. The more acidic phenols react very well in the absence of a catalyst. The reaction of oximes, and ketones that have substantial enolic contributions. 

ISODURENE (527-53-7) CioH, Combustible liquid. Forms explosive mixture in air (flash point 160°F/71°C Fire Rating 2). Contact with strong oxidizers may cause fire and explosion. Violent reaction with diazo compounds. On small fires, use dry chemical powder (such as Piuple-K-Powder), alcohol resistant foam. 

Carboxylic acids can be converted to esters with diazo compounds in a reaction essentially the same as 10-15. In contrast to alcohols, carboxylic acids undergo the reaction quite well at room temperature, since the reactivity of the reagent increases with acidity. The reaction is used where high yields are important or where the acid is sensitive to higher temperatures. Because of availability, the diazo compounds most often used are diazomethane (for methyl esters) ... 

A Sandmeyer reaction leading to the 3-chloro derivatives was observed upon treatment of 3-diazotriazoles with aqueous hydrochloric acid [1898LA33 26JCS1729 78ZN(B)216]. 3-Diazotriazole was reduced to the parent triazole by treatment at 0°C with primary and secondary alcohols [86DIS(B) (46) 3052]. The mechanism is not clear, but the process may be envisaged as involving hydride transfer from the intermediate 244 obtained by nucleophilic addition of alcohols to the diazo compound (Scheme 70). 

Reaction between alkoxides or arox-ides and alkyl halides (Williamson) 0-14 Reaction between alkoxides or arox-ides and inorganic esters 0-15 Alkylation of alcohols or phenols with diazo compounds 0-16 Dehydration of alcohols 0-17 Transetherification 0-19 Alkylation of alcohols with onium salts... 

Chemically, the diazirines are remarkably unreactive and in this they contrast strongly with diazo compounds. They are unaffected by alkalies and are stable in the presence of quite strong acids. (They may be recovered unchanged from solution in lOiV sulfuric acid, though there is a slow reaction in more concentrated solutions.) They do not form complexes with inorganic cations in the way that many azo compounds do, and they are unreactive towards alcohols and dienophiles. They do, however, react with Grignard reagents to yield iV-substituted diazir-idines. 

Alcohols Yield Ethers.—With alkalies a similar reaction does not occur, the more stable diazotates being formed (p. 591). When heated with alcohols, however, the diazo compounds act in an exactly analogous way to that with water. In this case if an aliphatic alcohol... 

PHENYLTRIDECANE (123-02-4) CjsHji Combustible liquid (flash point 230°F/110°C). Violent reaction with bases, amines, amides, and inorganic hydroxides and with diazo compounds. Incompatible with nitric acid, strong oxidizers. On small fire use water spray, dry chemical powder (such as Purple-K-Powder), alcohol resistant foam, or CO2 extinguishers. PHILOSOPHERS WOOL (1314-13 -2) see zinc oxide. 

Intramolecular [3+2] cycloaddition reactions of unsaturated diazocarbonyl compounds as well as transition-metal-catalyzed intramolecular carbene-type reactions of diazo compounds constitute an important strategy in contemporary synthesis of alicyclic and heterocyclic systems [1]. In a program directed towards the synthesis of silaheterocycles according to this concept, we have used various silicon-functionalized (silyl)diazoacetates [2] as starting materials. In this communication, we report on the synthesis of silaheterocycles from a-(alkynyloxy)silyl-a-diazoacetates [3], which can be prepared easily by successive reaction of a silyl bis(triflate) with an alkyl diazoacetate and a propargyl alcohol [4],... 

Dimerization Reaction. Dimerization is another commonly encountered reaction of diazo compounds. Alcohol (16) is initially transformed into diazoester (17) with compound (1) and then converted to bisdiazocarbonyl compound (18). The Intramolecular coupling of this mixed diazo compound with a catalytic amount of Rh2 (OAc)4 produces a 1 1 mixture of (19) and (20). Furthermore, treatment of (19) with a catalytic amount of iodine quantitatively converts (19) to (20) (eq 12). ... 

Cooperative catalysis in multi-component reactions highly enantioselective synthesis of y-hydroxyketones with a quaternary carbon stereocenter, (b) X. Han, M. Gan, H. Qin, J. Ji, X. Zhang, L. Jiang, W. Hu, Synlett 2011, 1717-1722. Trapping of oxonium ylides with Michael acceptors highly diastereoselective three-component reactions of diazo compounds with alcohols and ben-zylidene Meldrum s acids/4-oxo-enoates. 

Iodorhodium(III) porphyrins generally lead to alkylrhodium(III) porphyrins (Scheme 42)398>. This is also true for the reaction with ethyl diazoacetate in the presence of HOAc or an alcohol, and the insertion product 412 (M = Rh) could not be detected, in contrast to the corresponding cobalt porphyrin. A mechanistic scheme, which includes the diverse reaction modes of metalloporphyrins towards diazo compounds, has been proposed by Callot 393,398). 

The catalytic activity of rhodium diacetate compounds in the decomposition of diazo compounds was discovered by Teyssie in 1973 [12] for a reaction of ethyl diazoacetate with water, alcohols, and weak acids to give the carbene inserted alcohol, ether, or ester product. This was soon followed by cyclopropanation. Rhodium(II) acetates form stable dimeric complexes containing four bridging carboxylates and a rhodium-rhodium bond (Figure 17.8). 

Carbenoids derived from the metal catalysed decomposition of diazo compounds undergo various chemical transformations. Control of chemoselectivity by choice of the appropriate catalyst has significantly increased the synthetic viability of catalytic cyclopropanation reactions. Intermolecular reaction of unsaturated alcohols with carbenoids derived from catalytic decomposition of alkyl diazoesters has been reported by Noels and... 

Conversion of stabilized diazo compounds to hydrocarbons does not depend upon the reducing action of ethyl alcohol, for the reaction takes place smoothly in acetone, ether, nitrobenzene, benzene, chloroform, apd carbon tetrachloride. No acetaldehyde is produced when ethanol is the solvent. In the absence of metals, however, when the stabilized salts of diazotized a-naphthylamine are treated with ethyl alcohol, acetaldehyde, naphthalene, a-ethoxynaphthalene, and tar are obtained. 

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