Reaction with diazo alkanes

Halogenated and halogenoalkyl substituted imines react with diazo alkanes under very mild conditions and preferentially yield aziridines [5, 146 147] Diazonium betaines have been considered as intermediates of these reactions [148,... 

Enol Ethers and Esters 0-15 O-Alkylation of carbonyl compounds with diazo alkanes 0-17 Transetherification 0-20 Reaction between acyl halides and active hydrogen compounds 0-23 Transesterification 0-24 Acylation of vinylic halides 0-94 Alkylation with ortho esters 0-107 O-Acylation of 1,3-dicarbonyl compounds... 

The 4-monosubstituted phosphabenzene (102) has been obtained from the corresponding 1,4-dihydrostannin by reaction with phosphorus tribromide. Phosphorins having one carbon- and one oxygen-linked substituent on phosphorus may be made directly by the reaction of phosphorins (103) with diazo-alkanes in the presence of alcohols or phenols. ... 

Polyfluoroalkyl- andperfluoroalkyl-substituted CO and CN multiple bonds as dipolarophiles. Dmzo alkanes are well known to react with carbonyl compounds, usually under very mild conditions, to give oxiranes and ketones The reaction has been interpreted as a nucleophilic attack of the diazo alkane on the carbonyl group to yield diazonium betaines or 1,2,3 oxadiazol 2 ines as reaction intermediates, which generally are too unstable to be isolated Aromatic diazo compounds react readily with partially fluorinated and perfluorinated ketones to give l,3,4-oxadiazol-3-ines m high yield At 25 °C and above, the aryloxa-diazolines lose nitrogen to give epoxides [111]... 

Trifluoromethyl-substituted diazonium betaines [176]. Synthetic routes to trifluoromethyl-substituted diazo alkanes, such as 2,2,2-trifluorodiazoethane [ 177, 7 78, 179] and alkyl 3,3,3-trifluoro-2-diazopropionates [24], have been developed Rhodium-catalyzed decomposition of 3,3,3-tnfluoro-2-diazopropionates offers a simple preparative route to highly reactive carbene complexes, which have an enormous synthetic potential [24] [3-1-2] Cycloaddition reactions were observed on reaction with nitnles to give 5-alkoxy-4-tnfluoromethyloxazoles [750] (equation 41)... 

A neutral diazo compound can be considered as both a nucleophile and an electrophile. Thus, it can be substituted by the combination of an electrophilic moiety and a nucleophilic moiety (X+ Nu ") (Scheme 8). In practice, the diazomethyl group is transformed to the fluoromethyl group by treatment with hydrogen fluoride/pyridine mixture (70 30 w/w) (X = H Nu = F), or to the halofluoromethyl group by addition of A-halosuccinimide in the same medium (X = Cl, Br, I Nu = F), e.g. formation of l.16 The reaction can be performed on secondary diazo alkanes, diazo ketones or diazo esters.16 90 316... 

The importance of a-diazo ketones as synthetic intermediates has led to the development of a number of general methods for their preparation.5 Particularly popular approaches include the acylation of diazo alkanes and the base-catalyzed "diazo group transfer" reaction of sulfonyl azides with 8-dicarbonyl compounds.6-7 While direct diazo transfer to ketone enolates is usually not a feasible process,8-9 diazo transfer to simple ketones can be achieved in two steps by employing an indirect deformylative diazo transfer strategy in which the ketone is first formylated under Claisen condensation conditions, and then treated with a sulfonyl azide reagent such as p-toluenesulfonyl azide.6a,6c,9,i0,11... 

The C-a-metallated diazo alkane complex 63 when reacted with phenyliso-cyanate is transformed into the 1,2,3-triazolato zirconocene enolate complex 74. An identical reaction conducted with naphthyl isocyanate gave the triazole 75. It is reasonable to propose for the formation of 74 and 75, as a first step of the reaction, a [3 + 2] dipolar cycloaddition of the diazo function with the isocyanate group, with transient formation of 72 and 73 (Scheme 16). Then, due to the high... 

Together with the addition of C-nucleophiles, cycloadditions represent the most important reaction for the formation of C-C-bonds with the fullerene framework [28, 29, 110]. [3+ 2]Cycloaddition of diazo alkanes to 6-6 bonds was... 

Alkylation describes the reaction where an active hydrogen is replaced with an alkyl group, for example, a methyl group. Most polar groups can be alkylated, and many reagents can be used, for example, alkyl halogenides, diazo alkanes, and N,N -dimethylformamide dialkyl acetal. An example of an alkylation is the formation of methyl esters of fatty acids by using methanolic BF3, where boron trifluoride (BF3) acts as a catalyst. 

Organic compounds Organic fluorine compounds arc made by reaction of the corresponding alkane chloro-compounds with silver fluoride, mercurous fluoride, antimony trifluoride, titanium tetrafluoridc. and the arene fluoro-compounds by the diazo-reaction using hydrogen fluoride, and otherwise. The effect of the continued replacemenl of hydrogen atoms by fluorine atoms is an initial increase in reactivity, followed by a reversal of this effect, so lhal the highly substituted compounds arc relatively inert, See also Fluorocarbon. 

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