three-component procedure for the synthesis of new chiral spirooxindolopyrrolizidines via catalytic highly enantioselective 1,3-dipolar cycloaddition

the catalytic highly regio-, diastereo-, and enantioselective synthesis of a small library of spiropyrrolizidineoxindolesvia a four-component 1,3-dipolar cycloaddition reaction of azomethine ylides, derived from isatin, with electron-deficient dipolarophilewas described. the process occurs at room temperature in aqueous ethanol as a green solvent and in the presence of a bidendatebis(imine)–cu(ii)triflate complex as catalyst.the reaction mechanism is discussedon the basis of the assignment of the absolute configuration of the cycloadducts.the catalytic highly regio-, diastereo-, and enantioselective synthesis of a small library of spiropyrrolizidineoxindolesvia a four-component 1,3-dipolar cycloaddition reaction of azomethine ylides, derived from isatin, with electron-deficient dipolarophilewas described. the process occurs at room temperature in aqueous ethanol as a green solvent and in the presence of a bidendatebis(imine)–cu(ii)triflate complex as catalyst.the reaction mechanism is discussedon the basis of the assignment of the absolute configuration of the cycloadducts.