Conjugate Addition of 3-Buytn-2-one to Anilines in Ethanol: Alkene Geometric Insights through In Situ FTIR Monitoring
作者:David R. Chisholm、Roy Valentine、Ehmke Pohl、Andrew Whiting
DOI:10.1021/acs.joc.6b01110
日期:2016.9.2
A convenient, mild and effective conjugateaddition of 3-butyn-2-one to a variety of anilines in ethanol is reported. The reaction was monitored and characterized through in situ FTIR, and the dynamics of the facile E/Z alkene geometry interconversion of the resultant aniline-derived enaminones was explored through NMR, FTIR and X-ray crystallography. A straightforward purification protocol that employs
A Method for the Preparation of β-Amino-α,β-unsaturated Carbonyl Compounds: Study of Solvent Effect and Mechanism
作者:Reyno R. S.、Akash Sugunan、Ranganayakulu S.、Cherumuttathu H. Suresh、Goreti Rajendar
DOI:10.1021/acs.orglett.9b04531
日期:2020.2.7
An efficient method for the preparation of β-amino-α,β-unsaturated carbonylcompounds is demonstrated. Bench-stable sodium 3-oxo-enolates were prepared from carbonylcompounds, and reacted with amines in the presence of an acid and a desiccant. DFT studies revealed contrasting mechanisms toward the reactivity of aliphatic amines in protic solvents and aromatic amines in aprotic solvents. While the
(Z)-Enaminones are easily synthesized from poorly nucleophilic anilines and 4-methoxy-3-buten-2 one (an effective and inexpensive surrogate for 3-butyn-2-one) with impressive “on water” acceleration.
In the presence of catalytic amounts of trialkylsilyl triflate and triethylamine, unactivated amides react with imines to afford the corresponding Mannich-type adducts in high yields with high anti selectivities. While silicon enolates have been widely used in organic synthesis for four decades, this is the first example of the catalytic use of the silicon species, to the best of our knowledge. Moreover, it is noteworthy that unactivated simple amides bearing a-protons that are less acidic than those of ketones and aldehydes can be successfully used in catalytic direct-type addition reactions. Finally, a preliminary trial of an asymmetric catalytic version was conducted and showed promising enantioselectivity of the desired product.
Romussi; Parodi; Bignardi, Farmaco, Edizione Scientifica, 1986, vol. 41, # 7, p. 539 - 547