Ethyl diazoacetate, as source

Ethylenediamine, complexes with chro-mium(ll) salts, 52,62 Ethyl diazoacetate, as source of car-bethoxycarbene, 50,94 Ethylene, with p-methoxyphenylacetyl chloride and aluminum chloride to give 6-methoxy-d-tetralone, 51,... 

Esters, from diazoketones and organo-boranes, 53, 82 Esters, a-deuterio-, S3, 82 Esters, 7,6-unsaturated by Claisen rearrangement, 53,122 Ethers, by oxymercuration, 53, 96 Ethers, aryl methyl-, selective mono-demethylation of, 53, 93 Ethyl diazoacetate, as source of car-bethoxycarbene, 50, 94 Ethylenediamine, complexes with chromium(II) salts, 52, 62 Ethylene, with p-methoxyphenylacetyl chloride and aluminum chloride to give 6-methoxy-/3-tetralone,... 

Rh(Por)l (Por = OEP. TPP, TMP) also acts as a catalyst for the insertion of carbene fragments into the O—H bonds of alcohols, again using ethyl diazoacetate as the carbene source. A rhodium porphyrin carbene intermediate was proposed in the reaction, which is more effective for primary than secondary or tertiary alcohols, and with the bulky TMP ligand providing the most selectivity. ... 

Ligand 55c is also efficient in the cyclopropanation of other alkenes. 1,1 -Disub-stituted alkenes afford cyclopropanes in high enantioselectivity with ethyl diazoacetate as carbenoid source, Eq. 25 (34). Internal dissymetric trans alkenes are also excellent substrates. trans-P-Methyl styrene afforded a 95 5 diastereomeric mixture with cyclopropane 56a predominating in 96% ee, when the butylated hydroxy toluene (BHT) diazoester was used, Eq. 26 (35). 

House has similarly prepared an ester substituted [4.3.1]propellane (16) by employing ethyl diazoacetate as a carbenoid source, then hydrogenated the cyclopropane ring. In view of his motivation the formation of a mixture of epimeric esters does not matter. 

Cyclopropanation reactions were carried out with ethyl diazoacetate as car-bene source and styrene, using petroleum ether as solvent (Scheme 15). After completion of the reaction, the mixture was filtered in order to separate catalyst and products. The heterogeneous system provided slightly higher yields (up to 90%) and similar lower diastereoselectivities compared to the homogeneous system. 

Retrosynthetic analysis of TM 5.13 starts with the logical disconnection of the cyclopropane ring to ethyl diazoacetate as the source of carbene and cyclohexene... 

The substrate scope of the Cu(II)-catalysed reaction of ene-biscarbonyls (76) with two common diazo compounds (i.e., dimethyl diazomalonate and ethyl diazoacetate) as car-benoid sources has been broadened. Depending on the electronic/steric nature of both the ene-biscarbonyl and the diazo compound, moderate to excellent levels of chemose-lectivity have been achieved, the products usually formed being the dihydrofurans (77), dihydrobenzoxepines (78), and dihydrooxepines (79). 

Other types of bis(oxazoline) ligands have been tested using the reaction of styrene and ethyl diazoacetate. Of note is Nishiyama s py-box-ip hgand lb, which was used in 2 mol% and with [Ru(ll)Cl2(p-cymene)]2 as a metal source. The best result from these conditions was a yield of 73%, trans/cis ratio of 91 9 with a trans enantiomeric excess (ee) of 89% and a cis ee of 79%, as shown in Figure 9.13. The selectivity observed in Nishiyama s reaction can be explained by the following model, shown in Figure 9.14. This model shows the ligand-metal-substrate... 

There are examples of all metals from groups 8 to 11 to catalyze the transfer of a carbene group from a diazo compound to organic substrates. One of the most studied transformation is the olefin cyclopropanation reaction, " for which the use of Tp ML catalysts has provided valuable improvement. Thus, the diastereoselectivity of this reaction, that usually leads to mixtures of both cis and trans isomers, was directed toward the d.y-cyclopropane with the complex Tp Cu(thf) (hydrotris [3-mesitylpyrazolyl]borate) as the catalyst, affording a 98 2 cisdrans mixture with styrene (Scheme 5) and ethyl diazoacetate (EDA) as the carbene source. Other olefins were also cyclopropanated with the preferential formation of the cis isomer. The catalysts can be prepared in situ by mixing a Cu(I) source and the MTp salt. Also, the Tp Cu(NCMe) complex has been employed as catalyst in a fluorous phase for the styrene cyclopropanation reaction. ... 

Even thiophene itself will react with carbenes, at sulfur, to produce isolable thiophenium ylides, and in these, the sulfur is definitely tetrahedral. The rearrangement of thiophenium bis(ethoxycarbonyl) methylide to the 2-substituted thiophene provides a rationalisation for the reaction of thiophene with ethyl diazoacetate, which produces what appears to be the product of carbene addition to the 2,3-double bond perhaps this proceeds via initial attack at sulfur followed by S C-2 rearrangement, then collapse to the cyclopropane. Acid catalyses conversion of the cyclopropanated compound into a thiophene-3-acetic ester. ° 2,5-Dichlorothiophenium bis(methoxycarbonyl)methylide has been used as an efficient source of the carbene simply heating it in an alkene results in the transfer of (Me02C)2C to the alkene. ... 

Carbon atom insertion. Ethyl diazoacetate (202) provides a source of carb-enes, which have been trapped as aziridine adducts of a wide rangeof imines. ... 

Diazo compounds are commonly used as a carbene source in organic chemistry. A few systems based on metals such as Ru and Rh have been reported for the transfer of carbenes from diazo compounds. P6rez and coworkers reported NHC-copper systems for carbene and nitrene transfer. In the first report, [Cu (Cl)(IPr)] was used for the transfer to olefins, amines, and alcohob [64]. The main transformation was the cyclopropanation of styrene with ethyl diazoacetate (Scheme 8.24). Monitoring of the reaction showed a fast formation of the product (90% conversion in 6 h). The absence of styrene does not lead to the decomposition of EDA even after a long period of time (13 h). Decent stereoselectivity was obtained with styrene (cisitrans 32/68) and cyclooctene exolendo 73/27). 

Cyclopropcmation reactions are challenging as they involve the formation of highly strained three-membered rings. Cydopropane rings can be synthesized from a diazo precursor in the presence of a metal catalyst under mild conditions (Scheme 9.1) [37]. Initially, commercially available ethyl diazoacetate was employed as the carbene source for cyclopropanation reactions, but subsequently, other diazo compounds were developed for various carbene-transfer reactions... 

Concerning the first variant, Bew et al. reported the use of AT-fluoropyridinium triflate as an F organocatalyst for the aziridine synthesis from imines and ethyl diazoacetates [114]. Catalytic amounts of the fluorinated pyridinium salt 14 are claimed by the authors to function as a source for the fluorenium cation F which presumably activates the imine component, thus facilitating the following nucleophilic attack of ethyl diazoacetate leading to the aziridine system (Scheme 11). 

Successful conditions for intermolecular carbene insertions into alkane C-H bonds with diazo esters have been reported under Ag(I) and Ir(III) catalyses. While the argen-tate trinuclear cluster (90) has been shown to catalytically promote such C-H insertion with ethyl diazoacetate, " Ir(III)-based porphyrin catalyst (91) appeared much more efficient using bulky methyl 2-phenyldiazoacetate as an alternative carbene source. Ir(III)-based porphyrin analogue (92) bearing chiral arms promotes carbene insertion with up to 98% yield in an asymmetric manner (up to 98% ee). ... 

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