A silver-catalyzed stereoselective domino cycloisomerization–vinylogous aldol reaction of <i>ortho</i>-alkynylbenzaldehydes with 3-alkylidene oxindoles: an entry to functionalized isochromenes
Krishna Kumar, Bhuvnesh Singh, Ravi P. Singh
Abstract
A silver tetrafluoroborate catalyzed domino cycloisomerization-vinylogous aldol addition sequence on a multifunctional substrate such as ortho-alkynylbenzaldehydes yielding functionalized 1H-isochromenes in a single step with high yield and excellent diastereoselectivity (>19 : 1) is described. The reaction was well tolerated by alkyl, aryl, and unsubstituted alkynylbenzaldehydes, and furnished selective 6-endo-dig adducts exclusively without loss in the regio- as well as diastereoselectivity.
Topics & Concepts
CycloisomerizationDominoAldol reactionCascade reactionYield (engineering)StereoselectivityCatalysisChemistrySubstrate (aquarium)StereochemistryOrganic chemistryBiologyMaterials scienceEcologyMetallurgyCatalytic Alkyne ReactionsCatalytic C–H Functionalization MethodsSynthesis of Indole Derivatives