Catalytic Asymmetric Inverse-Electron-Demand Hetero-Diels–Alder Reaction of Dioxopyrrolidines with Hetero-Substituted Alkenes

Abstract

A highly efficient enantioselective inverse-electron-demand hetero-Diels-Alder reaction of dioxopyrrolidines with heterosubstituted alkenes has been realized by using a N, N'-dioxide/Ni(II) complex as the catalyst. A series of chiral bicyclic dihydropyranes were generated in excellent yields, good dr, and excellent ee values. Besides, a catalytic cycle with a possible transition state was proposed.

IronIII-catalyzed asymmetric inverse-electron-demand hetero-Diels–Alder reaction of dioxopyrrolidines with simple olefins

“…The comparison with the reaction of heterosubstituted alkenes which could be performed with Ni II complexes manifested critical of the Lewis acidity of the catalyst. 20 Using 10 mol% of In(OTf) 3 in CH 2 Cl 2 at 35 °C, the cycloaddition product was isolated in 84% yield and 48 : 52 endo : exo , which is selected to identify optimal chiral ligands to control the stereoselectivity. Noteworthily, the diastereoselectivity is poor, differing from the preferred endo -selectivity of achiral Lewis acid-promoted IEDHDA of β,γ-unsaturated α-ketoesters.…”

Nickel-Catalyzed Regiodivergent Asymmetric Cycloadditions of α,β-Unsaturated Carbonyl Compounds

“…Asymmetric hetero-Diels-Alder reactions have attracted considerable attention due to their ability to produce optically active heterocyclic molecules. [65][66][67][68][69][70][71] We conjectured that this nickel-catalyzed system was applicable to the inverse-electron-demand oxa-Diels-Alder ([4+2] annulation) of the α,β-unsaturated 2-acyl imidazoles once employing electron-rich alkenes as dienophiles. Indeed, under the identical conditions and in the presence of the same chiral nickel catalyst, the reaction of 2,3-dihydrofuran (2r) with the imidazole or benzimidazole substrates (1a, 1i-1s) gave the chiral bicyclic products (5a-5l) in 75-91% yields, with 11:1->20:1 dr and 87-Page 14 of 25 CCS Chemistry 97% ee (Scheme 5).…”

Asymmetric Addition and Cycloaddition Reactions with Ylidene‐Five‐Membered Heterocycles

“…Two years later, a similar Ni catalyst complex with a L ‐proline‐derived dioxide ligand L3 was used by the same authors to carry out an inverse‐electron‐demand hetero‐Diels−Alder reaction [94] . 4‐Arylidene‐2,3‐dioxopyrrolidines reacted as heterodienes with hetero‐substituted alkenes to give the corresponding fused pyrano‐pyrroles with excellent yields and stereoselectivities, regardless of the electronic or steric features of the substituents on the exocyclic double bond.…”