Diazomethane coupling reactions with

Another interesting coupling reaction with enamines was recently observed with bis(methylsulfonyl)diazomethane 22... 

Thioamides of two cyclopropanecarboxylic acids undergo coupling reactions with diazomethane derivatives in refluxing benzene containing rhodium(II) acetate. The reaction conceivably takes place via a thiirane intermediate which undergoes reductive elimination by reaction with excess diazo compound. An example of an intramolecular reaction is the formation of indolizine 2. If the diazo compound is not in excess a thiol is formed, this can be removed by Raney nickel desulfurization. ... 

Methylene chloride as solvent for diazomethane etherifications, 41, 9 Methylene cyclohexane, 40, 66 Methylene iodide, reaction with zinc-copper couple and cyclohexene, 41, 73... 

Compared to diazonium salts, diazo compounds are generally much less reactive towards nucleophiles than towards electrophiles. As a result of this azo coupling reactions of diazo compounds are the exception rather than the rule. Electron withdrawing substituents on the diazo carbon increase the reactivity towards nucleophiles. Consequently the ability to undergo azo coupling reactions increases from diazomethane to diazocarbonyl- and 2-diazo-l, 3-dicarbonyl compounds. Among the earliest reactions known were those with cyanide and sulfite ions Tertiary phosphines, as opposed to amines, can form stable addition complexes with diazoalkanes probably due to the ability of phosphorus to stabilize the betaine with its empty d orbitals (6). 

Azo Coupling Reactions Structures and Mechanisms In 1969 the first example was reported of a coupling reaction of diazomethane with... 

The reactions illustrated in equations (62-64) are each catalyzed by rhodium acetate. Diazo compounds, especially diazoalkanes, can also react by a simple ionic mechanism. The esterification of a carboxylic acid with diazomethane is a familiar example. The ionic pathway is especially likely when the intermediate carbocation would be stabilized. Thus, diazine (158) couples smoothly with phenols, presumably by thermal rearrangement to the corresponding diazo sugar, followed by acid-catalyzed N2 loss... 

Aromatic diazonio groups may be mentioned her due to their — at least formal -similarity to nitrile groups. In 1955 Huisgen and Koch investigated the reaction of 4-nitrobenzenediazonium chloride with an excess of diazomethane. They found that diazomethane reacts as a C-nucleophile in an azo coupling reaction (see Zollinger, 1994, Sect. 12.6, p. 339). In ether, 12% of l-(4-nitrophenyl)-l//-tetrazole (6.102) was, however, also found and Reimlinger et al. (1970) isolated l-(l//-pyrazol-5-yl)-li/-tetrazole (6.103) in 24% yield from pyrazole-3-diazonium chloride and diazomethane. 

Azafluoranthene bases have been found to date only within the family Menisper-maceae. A recent addition to this small group of optically inactive alkaloids is norrufescine, C18H15NO4, whose PMR spectrum is close to that of the known base rufescine. Diazomethane 0-methylation of norrufescine generated rufescine. The location of the phenolic function in ring D was confirmed by a positive coupling reaction of the alkaloid with /7-nitrobenzenediazonium chloride. ... 

Alkoxycarbonyl or acyl substituents usually render the hydroxypyrroles alkali-soluble, capable of coupling with diazonium salts, of being nitrosated, O-acylated and, in a few cases, O-methylated by diazomethane. Hydroxypyrroles carrying alkoxycarbonyl or acyl groups adjacent to the hydroxyl group give colour reactions with ferric ions. Some hydroxypyrroles give... 

Diazomethane is a valuable and useful agent in organic synthesis that can be employed as a Ci building block in many single-step chemical reactions, for example, the methylation of alcohols or phenols, esteriflcations of carbonic adds, cyclopropanation reactions with alkenes, the synthesis of heterocycles, and the synthesis of a-diazoketones from acid chlorides or anhydrides. In general, the reactions proceed with release of nitrogen. Usually, diazomethane is freshly prepared from N-methyl-nitroso compounds and aqueous KOH solution and can be stored as a cooled solution for a couple of days. However, its low boiling point... 

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