Alkyl Diazoacetates Research Articles

ChemInform Abstract: Reaction of Methyl 2-Acetylaminoacrylate with Alkyl Diazoacetates.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

ChemInform Abstract: Catalytic Enantioselective 1,3‐Dipolar Cycloadditions of Alkyl Diazoacetates with α,β‐Disubstituted Acroleins.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

An Organocatalytic Synthesis of cis‐N‐Alkyl‐ and N‐Arylaziridine Carboxylates

AbstractAn extremely mild protocol that employs readily available starting materials, i.e., aldehyde, amine and alkyl diazoacetate, returns structurally diverse N‐substituted‐C‐2/3‐difunctionalised aziridines in excellent yields and stereoselectivities when pyridinium triflate is incorporated as an organocatalyst. The reaction process is environmentally benign affording water and nitrogen as the only by‐products. This racemic protocol paves the way for the development of novel asymmetric organocatalysts capable of generating optically active aziridines.

Catalytic enantioselective 1,3-dipolar cycloadditions of alkyl diazoacetates with α,β-disubstituted acroleins

A catalytic route to highly functionalized chiral 2-pyrazolines by an asymmetric 1,3-dipolar cycloaddition reaction of ethyl diazoacetate with alpha-substituted and alpha,beta-disubstituted acroleins has been developed; in the presence of chiral (S)-oxazaborolidinium ion as catalyst, the reaction proceeded with high to excellent enantioselectivities (up to 99% ee).

Synthesis and properties of stable 1,2,3,4,5,6,7-heptamethoxycarbonylcyclohepta-2,4,6-trien-1-yl potassium and its reactions with electrophilic reagents

A new original one-pot procedure for the synthesis of a heptaester substituted cycloheptatriene from simple starting compounds, alkyl diazoacetate and 2,3-dibromosuccinate in pyridine was discovered. This compound, upon action of base, easily gives rise to the corresponding cycloheptatrienyl anion, which can be isolated as a stable salt. NMR and X-ray data of the compounds obtained are given. Reactions of this anion with electrophiles (methyl iodide, allyl bromide and diazonium salts) were also studied. In the last case, the 3a,7a-dihydroindazole derivatives were obtained as isolated products.

Silver‐Catalyzed [2,3]‐Rearrangement of Halonium Ylides Derived from Allyl and Propargyl Halides and Alkyl Diazoacetates.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.

Silver-catalyzed [2,3]-rearrangement of halonium ylides derived from allyl and propargyl halides and alkyl diazoacetates

A silver(I) complex derived from a polyfluorinated tris(pyrazolyl)borate effectively catalyzes carbene transfer to allylic and propargylic halides, leading to the formation of alpha-haloacetate derivatives.

Enantioselective 1,3‐Dipolar Cycloaddition Reaction Between Diazoacetates and α‐Substituted Acroleins: Total Synthesis of Manzacidin A.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.

Reactions of Alkyl Diazoacetates with Pyridinium Ylides.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.

Enantioselective 1,3-Dipolar Cycloaddition Reaction between Diazoacetates and α-Substituted Acroleins: Total Synthesis of Manzacidin A

A titanium BINOLate catalyzed asymmetric 1,3-dipolar cycloaddition reaction between alpha-substituted acroleins and alkyl diazoacetates has been developed. With this methodology in hand, chiral 2-pyrazolines containing a quaternary stereogenic center were obtained in high to excellent enantioselectivities (up to 95% ee). The synthetic utility of the optically enriched 2-pyrazoline thus obtained was demonstrated in the short synthesis of manzacidin A.

Synthesis of 17-epi-Calcitriol from a Common Androstane Derivative, Involving the Ring B Photochemical Opening and the Intermediate Triene Ozonolysis

An efficient synthesis of 17-epi-calcitriol 2, an epimer of natural hormone, via 17-epi-cholesterol 5a is described. Synthesis of 5a includes palladium-catalyzed cyclopropanation of the common androstane derivative 7 with an alkyl diazoacetate, reductive fission of the less shielded side of cyclopropane carboxylic acid esters 6, oxidation of the products into acid 11a, and alkylation of ester 11b. Photolysis of 7,8-dedydro-17-epi-25-hydroxycholesterol 19b and consecutive thermal rearrangement gave a mixture of several products that was subjected to ozonolysis to provide, after chromatography, hydroxy ketone 3a. The silyl derivative 3b was coupled with the respective ring A building block.

Reactions of alkyl diazoacetates with pyridinium ylides

Pyridinium (methoxycarbonyl)methylide generated from (methoxycarbonyl)methyl-pyridinium halides under the action of K2CO3 reacts with alkyl diazoacetates in CH2Cl2 at 20 °C, resulting in the successive addition of three CHCOOMe fragments from the ylide to form 3,6-bis(alkoxycarbonyl)-4,5-diazaoctadienoic acid diesters. Heating of the latter in the presence of pyridine leads to their isomerization to give tetraalkyl tetrahydropyridazine-tetracarboxylates in high yields. Under more drastic conditions (refluxing xylene in the presence of pyridine), the acyclic tetraesters undergo another transformation to form pyrrole-tetracarboxylic acid esters in yields of up to 60%.

A synthesis of 17-epi-calcidiol

The first synthetic approach to 17-epi-calcidiol 4 and congeners is presented. Key steps of the synthesis involve Pd-catalyzed reaction of the androst-16-ene derivative 6 with alkyl diazoacetates producing the respective cyclopropane derivatives 5, and lithium in liquid ammonia reduction of 5 leading to 17α-pregnane-20-carboxylic acid derivatives 9. The side chain was attached to ester 19 in a known manner.

Are the pyrazolines formed from the reaction of [60]fullerene with alkyl diazoacetates unstable?

[60]Fullerene-fused pyrazolines 1 were prepared by the reaction of C 60 with alky diazoacetates under the solid-state high-speed vibration milling conditions as well as in toluene solution. Pyrazolines 1 were stable in refluxing toluene and its thermolysis process in 1,2-dichlorobenzene was investigated, the decomposition rates and activation energies of pyrazolines 1 were obtained. The current work demonstrated that the liquid-phase reaction of C 60 with alkyl diazoacetates undergoes via 1,3-dipolar cycloaddition pathway at room temperature, or proceeds via carbene mechanism at a temperature of refluxing toluene, thus clarifies the previous ambiguity of its reaction mechanism.

An easily recoverable and efficient catalyst for heterogeneous cyclopropanation of olefins

The cyclopropanation of olefins with alkyl diazoacetates were carried out by copper complexes of Schiff bases, derived from chitosan and substituted salicylaldehydes, as the catalysts. The catalysts showed high activity and up to 56% e.e. was achieved under optimal conditions; moreover, the catalysts could be easily recovered and reused after the reaction.

Palladium-Mediated Polymerization of Alkyl Diazoacetates To Afford Poly(alkoxycarbonylmethylene)s. First Synthesis of Polymethylenes Bearing Polar Substituents

Polymerization of alkyl diazoacetates [N2CHCO2R: R = Et (1a) and Me (1b)] mediated by PdCl2 in the presence of an amine gave poly(alkoxycarbonylmethylene)s [(CHCO2R)n: R = Et (2a,b), Me (3a,b)] bearing an ester group on every carbon atom of their main chains. MALDI−TOF−MS analyses of the polymers 2a and 3b indicated that the degree of polymerization of the polymers extended up to nearly 100. The Pd-mediated polymerization of 1a and 1b in the presence of pyridine afforded the polymers quantitatively after reprecipitation from CHCl3 into n-hexane. A mechanism of the polymerization initiated with a Pd-assisted nucleophilic attack of an amine to the monomers is proposed.

New Chiral Substituted 8‐Quinolinyl‐oxazolines as Ligands for Copper(I)‐catalyzed Asymmetric Cyclopropanation

AbstractNew chiral substituted 8‐quinolinyl‐oxazoline ligands have been synthesized and applied in the copper(I)‐catalyzed asymmetric cyclopropanation of styrene with alkyl diazoacetates. The steric effect in the ligands plays a significant role in the enantiocontrol in asymmetric cyclopropanation, while the electronic effect is less important.

Asymmetric cyclopropanation catalyzed by C 2-symmetric bis-(ephedrine)-Cu(II) complexes

The asymmetric cyclopropanation of styrene with alkyl diazoacetate was performed with a series of Cu(II) complexes of novel chiral ligands, which were derived from substitution of 1,3-dibromopropane, 1,2-dibromoethane, α,α′-dibromo- m-xylene and 2,6–bis(bromomethyl)pyridine with 1 R, 2 S-(−)-ephedrine. These prepared catalysts shown to be highly active in the enantioselective cyclopropanation with ee higher than 89% under the optimal conditions.

Catalytic Cyclopropanation of Alkyl 2-Allyl-2-acetylaminomalonate and Methyl N-(Acetyl)(phenyl)dehydroalanine with Alkyl Diazoacetates

Cyclopropane analogs of aspartic and adipic acids were prepared by catalytic cyclopropanation of dehydro amino acid derivatives with alkyl diazoacetates in the presence of catalyst (dirhodium tetraacetate).

Asymmetric cyclopropanation catalyzed by copper–Schiff’s base complexes

The asymmetric cyclopropanation of styrene with alkyl diazoacetate were performed with copper complexes of Schiff bases, derived from substituted salicylaldehydes and a new chiral amino alcohol, as the catalysts. The electronic and steric properties, as well as the position of those substituents show obvious effects on the enantioselectivities, and ee higher than 98% were achieved under optimal conditions.