Novel Role of p-Toluenesulfonamide in the Preparation of 4,5-Diaminocyclopent-2-enones

Abstract

A new and efficient protocol for the preparation of 4,5-diaminocyclopent-2-enones via the reaction of N-sulfonylimine with secondary amines, with p-toluenesulfonamide acting as a leaving group, is presented. In addition, p-toluenesulfonamide worked well as a catalyst even with a catalytic amount for the reaction of 2-furaldehyde and secondary amines to afford the corresponding products in higher yields.

A New Approach to the Synthesis of Functionalized Bicyclo[3.2.1]octanes

“…We suppose that the intermediate 2 further undergoes spontaneous Nazarov-type 4π-electrocyclization [17] to give 2,3diaminocyclopentenones 3. The formation of 3 from furfural and amines is well known and described in recent literature (e.g., [18][19][20][21][22][23][24][25], see also the review by Piancatelli et al [26]). When furfural and isopropyl cyanoacetate were added to the reaction mixture, 3-(2-furyl)-2-cyanoacrylate 4 and Michael adduct 5 were formed sequentially.…”

High-Pressure Promoted Nazarov-like Electrocyclization Enables Access to trans-4,5-Diamino-cyclopent-2-enones Bearing Electron-Poor Anilines

“…4,5 Since the seminal work of Batey and co-workers on the use of lanthanides(III) in dry acetonitrile to access DCP, 6,7 alternative methods have employed ionic liquid 1-methylimidazolium tetrafluoroborate, 8 Dy(III)/Ni(III)-based heteronuclear clusters, 9−11 erbium(III) chloride, 12 and microwave irradiation in water, 13 thus increasing the kinetics of the reaction, decreasing the cost of the catalysts and/or increasing the sustainability of the process by the use of greener solvents. 14 Additionally, heterogeneous conditions have been described using silica-immobilized catalysts, 15 montmorillonite K10, 16 and metal−organic frameworks. 17 Additionally, Au(I) (i.e., Ph 3 PAuSbF 6 ) has been thoroughly used as a catalyst for the formation of cyclopentenones via Nazarov-like electro-cyclization, proving to be a robust methodology.…”

$$N$$ N -Polybenzylated alicyclic 1,2-diamines: cytotoxicity and G1 phase arrest in cancer cell line

“…In our search for original synthetic preparations of vicinal diamines, we were intrigued by the recent interest in a Ring-Opening/Ring-Closure (RORC) reaction between furfural and secondary amines [21][22][23][24][25]. Stenhouse et al explored this reaction with aromatic amines in presence of acidic catalysts more than 150 years ago to obtain compounds with dye properties [26][27][28][29].…”