Enantioselective synthesis of dihydropyrans. Catalysis of hetero Diels-Alder reactions by bis(oxazoline) copper(II) complexes was written by Evans, David A.;Johnson, Jeffrey S.;Olhava, Edward J.. And the article was included in Journal of the American Chemical Society in 2000.Synthetic Route of C6H12N2O4 This article mentions the following:
C2-sym. bis(oxazoline)-Cu(II) complexes catalyze the inverse electron demand hetero Diels-Alder reaction of α,β-unsaturated carbonyl compounds (heterodiene), e.g., (MeO)2P(O)COCR1:CR2R3 (R1, R3 = H, Me, R2 = Me, Ph, CHMe2, EtO, Et), with electron-rich olefins (heterodienophile), e.g., EtOCH:CH2, in high diastereo- and enantioselectivity. α,β-Unsaturated acyl phosphonates and β,γ-unsaturated α-keto esters and amides are effective heterodienes, while enol ethers and sulfides function as heterodienophiles. A range of substitution patterns is possible on the heterodiene: terminal alkyl, aryl, alkoxy, and thioether substituents are all tolerated. The enantioselective synthesis of dihydropyrans such as I by this method has been shown to be straightforward: cycloadditions may be conducted with as little as 0.2 mol % of the chiral catalyst and are readily run on multigram scale. The reactions exhibit a favorable temperature-enantioselectivity profile, with selectivities exceeding 90% even at room temperature A simple reaction protocol that employs a solid air-stable catalyst, convenient reaction temperatures, and low catalyst loadings is described. The utility of the derived cycloadducts in the preparation of chiral building blocks is demonstrated. Models for asym. induction are discussed considering product stereochem., X-ray crystallog. data for the solid catalysts, and mechanistic studies. In the experiment, the researchers used many compounds, for example, N1,N2-Dimethoxy-N1,N2-dimethyloxalamide (cas: 106675-70-1Synthetic Route of C6H12N2O4).
N1,N2-Dimethoxy-N1,N2-dimethyloxalamide (cas: 106675-70-1) belongs to amides. Amides are pervasive in nature and technology. Proteins and important plastics like Nylons, Aramid, Twaron, and Kevlar are polymers whose units are connected by amide groups (polyamides); these linkages are easily formed, confer structural rigidity, and resist hydrolysis. Amides are not in general accessible by the direct condensation of amines with carboxylic acids for two reasons: first, both components are readily deactivated by a transfer of a proton from the acid to the amine and second, the hydroxy unit on the carbonyl of the acid is a relatively poor leaving group. Nevertheless, the formation of five- and six-membered rings is often surprisingly simple provided that other factors can be brought into play to assist in the condensation.Synthetic Route of C6H12N2O4
Referemce:
Amide – Wikipedia,
Amide – an overview | ScienceDirect Topics