187950-52-3Relevant academic research and scientific papers
Intramolecular Cyclization of Vinyldiazoacetates as a Versatile Route to Substituted Pyrazoles
Drikermann, Denis,G?rls, Helmar,Kerndl, Valerie,Vilotijevic, Ivan
, p. 1158 - 1162 (2020/07/20)
Vinyldiazo compounds undergo a thermal electrocyclization to form pyrazoles in yields of up to 95percent. The reactions are operationally simple, use readily available starting materials, require no intervention of a catalyst, and enable the synthesis of mono-, di- A nd tri-substituted pyrazoles. With the ability to produce highly substituted pyrazoles and the flexibility in installing various types of substituents, this method constitutes a new entry to this valuable heterocyclic scaffold and may be of interest to all branches of the chemical industry.
Synthesis of Allylboranes via Cu(I)-Catalyzed B-H Insertion of Vinyldiazoacetates into Phosphine-Borane Adducts
Drikermann, Denis,M??el, Robert S.,Al-Jammal, Walid K.,Vilotijevic, Ivan
supporting information, p. 1091 - 1095 (2020/02/15)
Cu(I) catalysts enable C-B bond formation via direct insertion of vinyldiazoacetates into B-H bonds of borane-phosphine Lewis adducts to form phosphine-protected allylboranes under mild conditions. The resulting allylborane-phosphine Lewis adducts can be used in the diastereoselective allylation of aldehydes directly without the need for removal of the phosphine. The allylation reaction proceeds with high diastereoselectivity and yields 5,6-disubstituted dihydropyranones after treatment with an appropriate acid.
Synthesis of [18 F]-γ-Fluoro-α,β-unsaturated Esters and Ketones via Vinylogous 18 F-Fluorination of α-Diazoacetates with [18 F]AgF
Brooks, Allen F.,Ichiishi, Naoko,Jackson, Isaac M.,Lee, So Jeong,Sanford, Melanie S.,Scott, Peter J. H.,Thompson, Stephen
, p. 4401 - 4407 (2019/11/21)
This communication reports a method for the vinylogous radiofluorination of α-diazoacetates to generate [18 F]-γ-fluoro-α,β-unsaturated esters and ketones in moderate to good radiochemical yields. The method uses no-carrier-added [18 F]AgF and is compatible with aromatic and non-aromatic substrates and a number of different functional groups. The labeling method is showcased in the synthesis of a fluorinated cholest-5-en-3-one derivative as well as a difluorinated product pertinent to drug discovery.
A Stereospecific Access to Allylic Systems Using Rhodium(II)-Vinyl Carbenoid Insertion into Si-H, O-H, and N-H Bonds
Bulugahapitiya, Priyadarshanie,Landais, Yannick,Parra-Rapado, Liliana,Planchenault, Denis,Weber, Valery
, p. 1630 - 1641 (2007/10/03)
Rhodium-catalyzed decomposition of α-vinyldiazoesters in the presence of silanes, alcohols, ethers, amines, and thiols have been shown to produce the corresponding α-silyl, α-hydroxy, α-alkoxy, α-amino, and α-thioalkoxy esters in generally good yield with a complete retention of the stereochemistry of the double bond of the diazo precursor. An extension of the process in homochiral series has also been devised using either a chiral auxiliary attached to the ester function or achiral α-vinyldiazoesters and Doyle's chiral catalyst Rh2(MEPY)4. In the former approach, pantolactone as chiral auxiliary gave diastereoselectivities of up to 70%, while the second approach produced the desired allylsilane with ee as high as 72%. On the other hand, Rh2(MEPY)4-catalyzed insertion into the O-H bond of water led to poor or no enantioselectivity in good agreement with recent literature reports.
