Regioselective synthesis of novel dispiropyrrolidine and dispiropyrrolizidine oxindole derivatives via azomethine ylide specific [3+2]-cycloaddition†
Abstract
Structurally complex spiro analogues of indenoquinoxaline have been synthesized via the cycloaddition reaction of azomethine ylides with alkyl indeno[2,1-b]quinoxalin-11-ylidene acetate dipolarophiles in a highly regioselective and stereoselective manner. The structure and relative stereochemistry of the cycloadducts were confirmed using 1H and 13C-NMR spectroscopic methods, and single crystal X-ray diffraction studies.