Diazomalonic acid dimethyl ester

Dimethyl diazomalonate Malonic acid, diazo-, dimethyl ester (8) Propanedioic acid, diazo-, dimethyl ester (9) (6773-29-1)... 

In a model study, Helquist and co-workers described the reaction of dimethyl diazomalonate 128 with benzonitrile to prepare 5-methoxy-2-phenyl-4-oxazolecar-boxylic acid methyl ester 129 nearly quantitatively (Scheme 1.35). Several other 2-aryl-5-methoxy-4-oxazolecarboxylic acid methyl esters were prepared analogously. In addition, 2-aIkyl(aIkenyl)-5-methoxy-4-oxazolecarboxylic acid methyl esters were also prepared, although the yields for aliphatic nitriles were not as good, unless the nitrile was used as solvent. Other metal salts—including Rh2 (NHAc)4, Cu(OTf)2, Cu(C2Hs-acac)2, Rh2(02CC3H7)4, and Rh3(CO)ie— were not as effective as Rh2(OAc)4 in this reaction. 

Allyldiethylamine behaves similarly, but the yields are low since neither the starting amine nor the products are stable to the reaction conditions. For the efficiency of the cyclopropanation of the allylic systems under discussion, a comparison can be made between the triplet-sensitized photochemical reaction and the process carried out in the presence of copper or rhodium catalysts whereas with allyl halides and allyl ethers, the transition metal catalyzed reaction often produces higher yields (especially if tetraacetatodirhodium is used), the photochemical variant is the method of choice for allyl sulfides. The catalysts react with allyl sulfides (and with allyl selenides and allylamines, for that matter) exclusively via the ylide pathway (see Section 1.2.1.2.4.2.6.3.3. and Houben-Weyl, Vol. E19b, pll30). It should also be noted that the purely thermal decomposition of dimethyl diazomalonate in allyl sulfides produces no cyclopropane, but only the ylide-derived product in high yield.Very few cyclopropanes have been synthesized by photolysis of other diazocarbonyl compounds than a-diazo esters and a-diazo ketones, although this should not be impossible in several cases (e.g. a-diazo aldehydes, a-diazocarboxamides). Irradiation of a-diazo-a-(4-nitrophenyl)acetic acid in a mixture of 2-methylbut-2-ene and methanol gave mainly l-(4-nitrophenyl)-2,2,3-trimethylcyclo-propane-1-carboxylic acid (19, 71%) in addition to some O-H insertion product (10%). ... 

Reaction of 2,3-dihydro-1,4-dioxin with ethyl diazopyruvate over (trimethylphosphino)copper(I) chloride produces dihydrofuroic ester (114) and a similar reaction with dimethyl diazomalonate, followed by acid hydrolysis, afforded the lactone ester (115) <85JOC4681>. 

An alternative synthesis of the sulhlimine by reaction of the penicillin (383) with ethyl azidoformate resulted in the azetidinone (384) in low yield (Numata et al., 1972). This product was probably the result of an electrocyclic rearrangement of the intially formed sulfilimine (385). Conversion of 385 to a deacetoxycephem (290) was accomplished by heating in the presence of an acid catalyst. An analogous ring opening reaction was also observed on thermal treatment of the penicillin ester with dimethyl diazomalonate in the presence of cupric sulfate as catalyst. The initially formed ylide (386) proceeded to rearrange in an electrocyclic manner to afford the azetidinone (387) in good yield (Numata et al., 1972). 

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