Acid promoted dimerization of β-amino-α,β-unsaturated amides affording bis(functionalized) pyrrolinones

Recent development in the synthesis of pyrrolin‐4‐ones/pyrrolin‐3‐ones

“…Bulkiness on the amide is detrimental to the dimerization, leading to pyrrolidinones 73d and 73e in lower yields under similar reaction conditions (Scheme 23). 19 Zhao and co-workers explored the synthesis of variety of pyrrolin-4-ones 75 via the treatment of enamino esters 74 with TBHP (t-butylhydroperoxide, 3 eq.) and TBAI (t-butylammonium iodide, 0.2 eq.)…”

“…Bulkiness on the amide is detrimental to the dimerization, leading to pyrrolidinones 73d and 73e in lower yields under similar reaction conditions (Scheme 23). 19 …”

Synthesis of 1H-Pyrrol-3(2H)-ones via Three-Component Reactions of 2,3-Diketo Esters, Amines, and Ketones

“…68.4 mg (yellow solid, 87% yield); mp = 74.6−76.3 °C; TLC R f = 0.59 (PE/ EtOAc = 2:1); 1 H NMR (400 MHz, CDCl 3 ) δ 7.36−7.30 (m, 5H), 2H),2H),5.22 (d,J = 12.3 Hz,1H),5.09 (d,J = 12.3 Hz,1H),4H),2H),4H), 1.50 (s, 3H); 13 C NMR (101 MHz, CDCl 3 ) δ 195.2, 179. 5,167.3,161.6 (d,J = 249.4 Hz),135.3,133.4 (d,J = 3.2 Hz),130.2 (d,J = 8.7 Hz),128.6,128.4,128.3,116.3 (d,J = 22.7 Hz),112.6,75.1,67.4,31.8,29.5,27.7,25.9,21.7,19.1;19 F NMR (376 MHz, CDCl 3 ) δ −113.2; HRMS (ESI-TOF) m/z: [M + Na] + Calcd for C 24 H 24 NO 3 FNa 416.1632; found 416.1631.…”

“…Due to their importance, many efforts have been undertaken for their syntheses and modifications . The main synthetic strategies occur by three routes: (1) dimerization of enamines (mediated by hypervalent iodine­(III) reagent, TBHP/TBAI system; catalyzed by p -TsOH, Cu­(TFA) 2 ); (2) cyclization of corresponding open-chain precursors (catalyzed by gold, platinum, copper; treated with I 2 , TEMPO, thermal cyclization); (3) transformations based on indolin-3-ones or indoles including Michael addition reaction, annulation reaction, rearrangement reaction, and oxidation reaction . Although considerable progress has been made in this field, the existing methods suffer from drawbacks such as narrow substrate scope and low availability of the starting materials.…”

K2S2O8/TEMPO-Induced Cascade Oxidative Cyclization/1,2-Migration of Electron-Deficient Groups: Strategy for the Construction of 1H-Pyrrol-2(3H)-ones

“…In this context, oxidative cyclization/1,2-carbon migration of enamines has attracted increasing attention. We and others have previously reported oxidative cyclization/1,2-methyl migration reactions of N -alkyl enamides or enaminones mediated by Cu­(II), iodine­(III), H 2 O 2 , TsOH, or oxoa-mmonium salt . This type of 1,2-carbon migration reactions followed an α-hydroxy imine rearrangement mechanism.…”