A cinchona alkaloid catalyzed enantioselective sulfa-Michael/aldol cascade reaction of isoindigos: construction of chiral bispirooxindole tetrahydrothiophenes with vicinal quaternary spirocenters
Palladium(II) Acetate-Catalyzed Dual C-H Functionalization and C-C Bond Formation: A Domino Reaction for the Synthesis of Functionalized (<i>E</i>)-Bisindole-2-ones from Diarylbut-2-ynediamides
A domino reaction of palladium(II)‐catalyzed dual C–H functionalization with subsequent intramolecular annulation is presented. This method provides a convenient synthesis of a range of symmetrical and unsymmetrical biologically important (E)‐bisindole‐2‐ones under extremely mild reaction conditions – room temperature, green oxidant and no additive. The reaction mechanism is elucidated in light of
tetrasubstituted olefins were synthesized in high yields and with low to high Z-selectivities from phenyldiazoacetates. For 3-diazooxindoles, isoindigo derivatives were provided in moderate to high yields and with excellent E-selectivities. Experimental results showed that the reaction proceeded through a diiodo intermediate. The synthetic usefulness of this reaction was illustrated by the synthesis of maleimide
The present work describes the 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU)-promoted self-dimerization of 9-chlorofluorenes and 3-chlorooxindoles for the preparation of the corresponding 9,9′-bifluorenylidene and isoindigo derivatives in moderate to good yields of 29–97%. The reactions proceed readily in a short reaction time under mild and metal-free conditions. Scale-up syntheses (5.0 mmol) of selected