Abstract The aldoladdition of acyldiazomethane with aromatic aldehydes, vinyl aldehyde and aliphatic aldehydes was carried out efficiently in the presence of MgI2 etherate and iPr2EtN (DIPEA) using untreated reagent-grade CH2Cl2 under atmospheric conditions in good to excellent yields. Iodide counterion and a non-coordinating reaction media (i.e. CH2Cl2) are among the critical factors for the unique
Directaldolcondensation of various aromatic, heteroaromatic, α,β-unsaturated aldehydes and aliphatic aldehydes with acyldiazomethane was realized using MgI2 etherate (MgI2·(Et2O)n) as a promoter in the presence of diisopropyl amine (DIPEA) in excellent yields in a short time under mild conditions with high chemoselectivity. Iodide counterion, and a non-coordinating less ploar reaction media (i.e
DBU-promoted condensation of acyldiazomethanes to aldehydes and imines under catalytic conditions
作者:Nan Jiang、Jianbo Wang
DOI:10.1016/s0040-4039(01)02375-9
日期:2002.2
The condensation of acyldiazomethanes to aldehydes and imines can be promoted with catalytic amount of DBU. The condensation gives β-hydroxy α-diazo carbonyl compounds or β-amino α-diazo carbonyl compounds in high yields.
A Lewis Acid-Catalyzed Diastereoselective Synthesis of Functionalized 2-Diazo-1,5-dicarbonyl Compounds
作者:Evan M. Howard、Matthias Brewer
DOI:10.1021/acscatal.1c03036
日期:2021.10.1
A diverse array of 2-diazo-1,5-dicarbonyl compounds were formed by the Lewis acid-catalyzed reaction of enoxysilanes with β-hydroxy-α-diazo carbonyls. This reaction proceeds via the Zn(OTf)2-catalyzed dehydroxylation of the β-hydroxy-α-diazo carbonyl to form a vinyl diazonium ion intermediate that is intercepted by the enoxysilane nucleophile to give diazo-containing scaffolds with increased molecular
Chemistry of Diazocarbonyl Compounds: XVIII. Synthesis and Spectral Parameters of 1,3-Dialkyl- 3-hydroxy-2-diazoketones
作者:O. V. Zhdanova、S. M. Korneev、V. A. Nikolaev
DOI:10.1023/b:rujo.0000034964.50578.fb
日期:2004.3
Reduction of the carbonyl groups in cyclic and acyclic 2-diazo-1,3-diketones with sodium tetra-hydridoborate in aqueous-alcoholic medium, followed by hydrolysis of the reaction mixture over wet silica gel and chromatographic purification on neutral aluminum oxide, afforded 1,3-dialkyl-3-hydroxy-2-diazoketones in 58-87% yield. Bulky substituents at the carbonyl group considerably reduce the efficiency of the process, and the reduction of cis- and trans-4,6-di-tert-butyl-2-diazocyclohexane-1,3-diones is characterized by low stereoselectivity (de 40-49%). In the IR spectra of 3-hydroxy-2-diazocyclohexanes, absorption bands corresponding to stretching vibrations of "free" axial hydroxy groups are located at higher frequencies (by 2045 cm(-1)) than those belonging to equatorial hydroxy groups. These parameters may be useful for conformational analysis of cyclic hydroxy diazo ketones. Stabilization of the E conformation of acyclic hydroxy diazo ketones via intramolecular hydrogen bonding is likely to occur only in nonpolar solvents (CCl4, cyclohexane).