A new methodology was developed for the synthesis of enantiomerically enriched 3,3-disubstituted 3-chlorooxindoles 3 via a Michael addition of 3-chloroxindoles to nitroolefins 2, catalyzed by chiral squaramide 10. Products with adjacent quaternary–tertiary centers were isolated in excellent yields (up to 99%), high diastereoselectivities (up to 11:1), and enantiomeric purities (up to 92%). This is
Asymmetric Organocatalytic Synthesis of Spiro-cyclopropaneoxindoles
作者:Tõnis Kanger、Artur Noole、Andrei Malkov
DOI:10.1055/s-0033-1338505
日期:——
Straightforward cascade reactions for the synthesis of spiro-cyclopropaneoxindoles are described. The target compounds are obtained in high yields and in good enantio- and diastereoselectivities via hydrogen bonding or iminium catalysis.