Copper-Promoted Ring-Opening Addition Of Cyclopropanols For Constructing Spiro Skeletons

The 3-spirocyclopentane oxindole skeleton is widely distributed in natural products and drugs with important biological activities.Although efficient methods,such as cycloaddition,cascade reactions,Heck reaction,Tomita’s zipper cyclization,and Piancatelli rearrangement,have been developed to construct the 3-spirocyclopentane oxindole skeletons,drawbacks including high expense of reagents and tetious preparation of reaction substrates remain.In this thesis,with the easily prepared 3-indolyl cyclopropanols as the substrates,we have developed an unprecedented Copper(II)chloride-promoted ring-opening addition of cyclopropanols to C3 position of the indole rings,providing a series of 3-spirocyclopentane oxindole compounds in high yields(up to 96%).This is the first example of dearomatization addition reaction of cyclopropanol to the electron-rich indole rings.This new method features easy preparation of substrates,cheap reagents,mild reaction conditions,and wide sustrate scope.