[3+2]-Annulation of oxindolinyl-malononitriles with Morita–Baylis–Hillman acetates of nitroalkenes for the regio- and diastereoselective synthesis of spirocyclopentane-indolinones

Synthesis of tetrahydrochromenes and dihydronaphthofurans via a cascade process of [3 + 3] and [3 + 2] annulation reactions: mechanistic insight for 6-endo-trig and 5-exo-trig cyclisation

“…The activation energy for the six-member ring cyclisation using the DFT method was in line with the previous literature report. 26 The product formation P-int3 with enthalpy of activation 13.37 kcal mol −1 . The proton transfer has occurred on P-int3 via P-TS4 with the activation energy of 30.85 kcal mol −1 has produced the final product of naphthopyran ( 3a ).…”

Recent advances in the synthetic applications of Morita–Baylis–Hillman and Rauhut–Currier adducts of nitroalkenes

“…In 2021, our group reported the synthesis of highly substituted spirocyclopentane-1,3′-indolinones 68 by exploring the 1,2-binucleophilic reactivity of oxindolin-3-yl-malononitriles 67 (Scheme 22). 32 The reaction of oxindolin-3-yl-malononitriles with MBH acetates of nitroalkenes 33 was carried out using DABCO, and the reaction proceeded in a formal [3 + 2] manner via a carba-S N 2′-carba-Michael pathway. The reaction mechanism was further confirmed using DFT calculations.…”

DABCO-Catalyzed Mono-/Diallylation of N-Unsubstituted Isatin N,N′-Cyclic Azomethine Imine 1,3-Dipoles with Morita-Baylis-Hillman Carbonates

“…MBH adducts contain the structural moieties of allylic alcohols or amines, Michael acceptors, and electron-withdrawing groups, which makes them valuable substrates for various types of reactions such as Michael addition, allylic substitution, cycloaddition reaction, Friedel-Crafts reaction, Claisen rearrangement, etc. [ 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49 , 50 , 51 , 52 , 53 , 54 , 55 , 56 , 57 , 58 ]. Based on our previous studies of 1,3-dipolar cycloaddition, Michael addition of azomethine ylides and azomethine imines and palladium-catalyzed tandem reaction to construct 3,3-disubstituted indolinones [ 59 , 60 , 61 , 62 , 63 , 64 , 65 , 66 , 67 , 68 ], herein we report the mono-/diallylation of isatin N , N ′-cyclic azomethine imines from the condensation of isatin and pyrazolidones with MBH carbonates.…”