Vinyldiazocarbonyl Compounds Research Articles

Chemical Synthesis of the ODM-201's Diastereomers through an Efficient Intramolecular 1,3-Dipolar Cycloaddition.

An efficient synthesis of ODM-201's diastereomers has been developed from (R)-methyl 3-hydroxybutanoate or (S)-methyl 3-hydroxybutanoate, respectively, with high overall yield and excellent diastereomeric purity. The key step in this synthesis is the preparation of the key intermediate (R)-5-(1-((tert-butyldimethylsilyl)oxy)ethyl)-1H-pyrazole-3-carboxylic acid or (S)-5-(1-((tert-butyldimethylsilyl)oxy)ethyl)-1H-pyrazole-3-carboxylic acid through intramolecular 1,3-dipolar cycloaddition of the vinyl diazo carbonyl compounds.

ChemInform Abstract: Diazo Strategy for the Synthesis of Pyridazines: Pivotal Impact of the Configuration of the Diazo Precursor on the Process.

AbstractZ‐configured vinylogous diazoesters undergo a diaza‐Wittig reaction providing pyridazines.

Diazo Strategy for the Synthesis of Pyridazines: Pivotal Impact of the Configuration of the Diazo Precursor on the Process.

Phosphazenes of vinyldiazocarbonyl compounds having cis stereochemistry of the functional groups on the vinyl bond readily produce pyridazines by a diaza-Wittig process, whereas their counterparts with trans configuration remain intact under similar reaction conditions. Upon UV irradiation trans-phosphazenes furnish pyridazines through a tandem trans-to-cis isomerization followed by intramolecular cyclization. At elevated temperatures trans-(triphenyl)phosphazenes dissociate to give the initial vinyldiazo compounds, which produce pyrazoles in high yields. The first theoretical study on the mechanism of the diaza-Wittig process by DFT calculations at the M06-2X/6-31G(d) level of theory suggest that for the cis-phosphazenes a rapid tandem [2+2] cycloaddition/cycloelimination process with low energy barriers is preferred over trans isomers.

ChemInform Abstract: Gold‐Catalyzed Cycloaddition Reactions of Ethyl Diazoacetate, Nitrosoarenes, and Vinyldiazo Carbonyl Compounds: Synthesis of Isoxazolidine and Benzo[b]azepine Derivatives.

AbstractA gold‐catalyzed three‐component reaction of vinyldiazo carbonyl compounds, nitrosobenzenes, and ethyl diazoacetate is developed to give diazo‐containing isoxazolines in high diastereoselectivities.

Gold‐Catalyzed Cycloaddition Reactions of Ethyl Diazoacetate, Nitrosoarenes, and Vinyldiazo Carbonyl Compounds: Synthesis of Isoxazolidine and Benzo[b]azepine Derivatives

AbstractGold‐catalyzed cycloadditions of ethyl diazoacetate, nitrosoarenes, and vinyldiazo carbonyl species to yield isoxazolidine derivatives stereoselectively are described. Treatment of these isoxazolidine products with the same catalyst results in a novel 1,2‐H shift/[3,3] rearrangement to give benzo[b]azepine compounds. The mechanism of this skeletal rearrangement is elucidated with deuterium‐labeling experiments.

Gold‐Catalyzed Cycloaddition Reactions of Ethyl Diazoacetate, Nitrosoarenes, and Vinyldiazo Carbonyl Compounds: Synthesis of Isoxazolidine and Benzo[b]azepine Derivatives

Gold-catalyzed cycloadditions of ethyl diazoacetate, nitrosoarenes, and vinyldiazo carbonyl species to yield isoxazolidine derivatives stereoselectively are described. Treatment of these isoxazolidine products with the same catalyst results in a novel 1,2-H shift/[3,3] rearrangement to give benzo[b]azepine compounds. The mechanism of this skeletal rearrangement is elucidated with deuterium-labeling experiments.

ChemInform Abstract: Thermolysis of Trifluoromethyl‐Containing Vinyldiazocarbonyl Compounds and X‐Ray Crystal Structure Analysis of Unexpected Reaction Products.

AbstractThermolysis of the title compounds results in the formation of different products due to different pathways of decomposition.

Effect of configuration of 2-vinyldiazocarbonyl compounds on their reactivity: experimental and computational study

Non-fluorinated vinyldiazo compounds with trans-configuration irrespective of the nature of 3-R(1)-substituent (R(1) = H, Me, TBSO) even under ambient conditions easily cyclize to produce pyrazoles, while cis-stereoisomers undergo similar ring closure only at elevated temperatures or decompose to produce vinyloxocarbene reaction products. The 3-CF3-substituted analogues with cis- or trans-configuration do not produce pyrazoles at all, but on heating furnish only vinylcarbene derived products. DFT calculations of theoretical energy barriers adequately explain the different experimental reactivity found for stereoisomeric vinyldiazocarbonyl compounds, and a new model for their interconversion through the corresponding pyrazoles has been suggested.

ChemInform Abstract: Influence of an Internal Trifluoromethyl Group on the Rhodium(II)‐Catalyzed Reactions of Vinyldiazocarbonyl Compounds.

AbstractIncorporation of a trifluoromethyl group into the starting compounds strongly reduces the tendency of intermediate vinyloxocarbenoids to undergo intermolecular reactions.

Thermolysis of trifluoromethyl-containing vinyldiazocarbonyl compounds and X-ray crystal structure analysis of unexpected reaction products

Two unusual compounds, 1,3a,6,6a-tetrahydro-3a,6a-bis(trifluoromethyl)-cyclopenta[c]pyrazol-3,4,5,6-tetracarboxylic acid tetramethyl ester (C16H14N2O8F6) (3) and 2-acetyl-5,7-bis(trifluoromethyl)-4-methyl-3-methoxy-2,4,6-cycloheptatrienecarboxylic acid methyl ester (C14H11F6O3) (4), were obtained from thermolysis of 3-trifluoromethyl-substituted vinyldiazocarbonyl compounds. The crystal structures of the products were determined as part of a larger comparison study on the thermal and Rh(II)-catalyzed reactions of F- and H-vinyldiazocarbonyl compounds. The resulting structures provide the first crystallographic characterization of bis(trifluoromethyl)substituted compounds of this kind. The pure compounds with all-carbon (4) and half-heterocyclic (3) skeletons are composed of a seven- and two-annulated five-membered rings in folded butterfly and envelope conformations, respectively.

Influence of an Internal Trifluoromethyl Group on the Rhodium(II)-Catalyzed Reactions of Vinyldiazocarbonyl Compounds

Incorporation of a trifluoromethyl group into the structure of 4-(alkoxycarbonyl)vinyldiazocarbonyl compounds greatly decreases the tendency of the carbenoid intermediates formed during Rh(II)-catalyzed reactions to undergo intermolecular processes. Instead, they are prone to experience intramolecular [1,5]- and [1,3]-electrocyclizations to produce reactive cyclopropenes and furans, and these are capable of further transformations.

Two-Stage Synthesis of 3-(Perfluoroalkyl)-Substituted Vinyldiazocarbonyl Compounds and Their Nonfluorinated Counterparts: A Comparative Study

Two approaches for the synthesis of fluorinated (<i>F</i>) and nonfluorinated (<i>H</i>) 4-(alkoxycarbonyl)-substituted <i>cis</i>- and <i>trans</i>-vinyldiazocarbonyl compounds with substituents of variable stereoelectronic nature (H, Me, Ph, CF₃, OTBS) at the C-3 atom of the vinyl double bond from the relevant 1,3-dicarbonyl compounds were compared: a pathway using the Wittig reaction followed by a diazo transfer reaction was most efficient for the synthesis of the <i>H</i>-vinyldiazocarbonyl compounds (total yields of up to 60%), while the yields of their <i>F</i>-analogues under similar conditions did not exceed 16–37%. An approach via diazo transfer followed by the Wittig reaction, in contrast, is more effective for the preparation of <i>F</i>-vinyldiazocarbonyl compounds (total yields 37–69%). The configuration of the resulting <i>F</i>- and <i>H</i>-vinyldiazocarbonyl compounds is evidently controlled by the steric bulk of the substituent at the C-3 atom of the vinyl double bond and, in addition, depends on the specific synthetic pathway.

Stereochemical aspect of the intramolecular diaza-wittig reaction

Reactions of fluoroalkyl-substituted vinyl diazo carbonyl compounds with triphenylphosphine are accompanied by spontaneous intramolecular cyclization of the initially formed phosphazene, and pyridazines are formed as a result of tandem process [1–3]. However, no analogous transformations occur with fluorine-free vinyl diazo carbonyl compounds. Taking into account that fluoroalkyl-containing vinyl diazo carbonyl compounds are usually characterized by cis configuration* of the double bond [1, 4] and that their fluorine-free analogs are trans isomers [5, 6], the most probable reason for their different reactivities is different arrangement of functional groups (CO2Alk, CN2) at the double C=C bond. The goal of the present work was to compare chemical transformations of diastereoisomeric fluoroalkyl-containing and fluorinefree phosphazenes derived from vinyl diazo carbonyl compounds.

Rhodium(II)-vinylcarbenoid insertion into the SiH bond. A new stereospecific synthesis of allylsilanes

Rh 2(OAc) 4 catalysed decomposition of vinyldiazocarbonyl compounds in the presence of organosilanes led stereospecifically to the corresponding allylsilanes in good yields. An asymmetric approach has also been considered as well as the extension of the methodology to the synthesis of other allylic systems.