A novel entry into a new class of spiroheterocyclic framework: regioselective synthesis of dispiro[oxindole-cyclohexanone]pyrrolidines and dispiro[oxindole-hexahydroindazole]pyrrolidines

The regioselective synthesis of spirooxindolo pyrrolidines and pyrrolizidines via three-component reactions of acrylamides and aroylacrylic acids with isatins and α-amino acids

“…A large number of focused libraries of spirooxindolo pyrrolidines and pyrrolizidines containing a wide set of natural and nonnatural α-amino acids [11–13], more than fifteen isatins [14], and 1,3-dipolarophiles, e.g. α,β-unsaturated ketones [15–17], maleimides [18–19], benzo[ b ]thiophene-1,1-dioxide [20], bis(arylmethylidene)acetones and -cycloalkanones [21–22], 1,4-naphthoquinone [23], arylidenemalonodinitriles [24], arylidenerhodanines [25–26], α,β-unsaturated lactones [27], nitrostyrenes [28], acrylic and propiolic esters [29], acrylonitriles [30] and arylidene-1,3-dimethylpyrimidine-2,4,6-triones [31] have been reported. However, the molecular diversity of suitable building blocks for construction of spirooxindoles is by far not exhausted with the above mentioned substances.…”