Direct Asymmetric Formal [3 + 2] Cycloaddition Reaction of Isocyanoesters with β-Trifluoromethyl <i>β,β</i>-Disubstituted Enones Leading to Optically Active Dihydropyrroles
A highly enantioselectivecopper-catalyzed [3 + 2] cycloaddition reaction of α-isocyanoesters with β,β-disubstituted enones has been developed. Dihydropyrroles were obtained in excellent yields and enantioselectivity by employing an inexpensive copper catalyst. This process provides a scalable and efficient route for the synthesis of highly enantioselective 2,3-dihydropyrroles bearing a trifluoromethylated
Efficient synthesis of trifluoromethylated dihydrochalcones, aryl vinyl ketones and indanones by superelectrophilic activation of 4,4,4-trifluoro/3-(trifluoromethyl)crotonic acids
作者:G.K. Surya Prakash、Farzaneh Paknia、Arjun Narayanan、Golam Rasul、Thomas Mathew、George A. Olah
DOI:10.1016/j.jfluchem.2012.07.008
日期:2012.11
Superacid catalyzed electrophilic substitution of arenes using 4,4,4,-trifluoro/3-trifluoromethylcrotonic acids has been investigated. The direct synthesis of various trifluoromethylated dihydrochalcones, aryl vinyl ketones and indanones has been achieved by this methodology. It has been found that the position of the trifluoromethyl group has a profound effect on the nature of the reaction and the products
Diastereo- and Enantioselective Copper(I)-Catalyzed Intermolecular [3+2] Cycloaddition of Azomethine Ylides with β-Trifluoromethyl β,β-Disubstituted Enones
Reported herein is an asymmetric [3+2] cycloaddition reaction of azomethine ylides with β‐trifluoromethyl β,β‐disubstituted enones, a reaction which is enabled by a Ming‐Phos‐derived copper(I) catalyst (Ming‐Phos=chiral sulfinamide monophosphines, Figure 2). This method provides scalable and efficient access to the highly substituted pyrrolidines with a trifluoromethylated, all‐carbon quaternary stereocenter
A catalyticasymmetric [3+2] cycloaddition of glycine ketimines with β‐CF3 β,β‐disubstituted enones was realized in the presence of a chiral copper(I)/Ming‐Phos complex. This method provides an access to construct highly functionalized pyrrolidines bearing threecontiguousstereocenters, which including a trifluoromethylated all‐carbon quaternary stereocenter. The features of this reaction include
The employment of β,β-disubstitutedenones as dipolarophiles poses a considerable challenge due to their steric hindrance and low reactivity. A copper-catalyzed asymmetric exo-selective dipolar cycloaddition of β-trifluoromethyl β,β-disubstitutedenones with azomethine ylides was developed, which provides an efficient access to valuable pyrrolidines bearing a trifluoromethylated all-carbon quaternary