https://www.selleckchem.com/pr....oducts/Etopophos.htm
Based on a novel umpolung strategy, an efficient and highly enantioselective cascade aldol/cyclization/tautomerization of the 2-(2-oxoindolin-3-yl)malononitrile to active carbonyl compounds with excellent diastereo- and enantioselectivity has been developed. Also, various enantio-enriched multifunctional dispiro[2-amino-4,5-dihydrofuran-3-carbonitrile]bisoxindoles with adjacent spiro-stereocenters were conveniently obtained by this novel methodology. Also, the dispiro[2-amino-4,5-dihydrofuran-3-carbonitrile]bisoxindoles were easily tr