A Lewis-Acid Catalyzed Synthesis of Substituted Oxindole Derivatives
摘要:
Lewis acid-catalyzed cyclization of various 2-(N-arylcarbamoyl)-methylenemalonates to give nitrogen-containing benzo-annelated heterocycles was investigated in terms of selectivity. Reaction of substrates with various alkyl groups on nitrogen proceeded to give oxindole derivatives. Cyclization reaction of diester-amides of MeO and halooen-substituted anilines in the presence of catalytic Lewis acid (ZnCl2, SnCl4, AlCl3, Zn(OTf)(2), Sc(OTf)(3), etc.) gave oxindoles in high yields. Interesting regioselectivity was observed for meta- halogen substrates. Dimethoxyisoquinoline analogs were also obtained by this reaction using a catalytic Lewis acid.
[3+2]-Annulation of oxindolinyl-malononitriles with Morita–Baylis–Hillman acetates of nitroalkenes for the regio- and diastereoselective synthesis of spirocyclopentane-indolinones
作者:Abhishek Pareek、Sudheesh T. Sivanandan、Shweta Bhagat、Irishi N.N. Namboothiri
DOI:10.1016/j.tet.2022.132650
日期:2022.2
highly regio- and stereoselective [3 + 2] annulation with 1,3-bielectrophilic nitroallylic acetates leading to spirocyclopentane-indolinones. The reaction takes place in the presence of DABCO in THF at room temperature and affords the multi-functional spirocyclic compounds possessing three chiral centers, including a spiro-chiral center in good to excellent yields and short reaction time. The key role