Unusual Reactions of Magnesium Indolates with Benzenesulfonyl Chloride

Article abstract of DOI:10.1021/jo00391a044

Grignard reagents from N-unsubstituted indoles and benzenesulfonyl chloride undergo reaction such as to produce unstable intermediates of β-chlorination and α-sulfonylation, which are transformed into oxindoles or substituted indoles.In the same reaction, yuehchukene (the naturally occurring dehydroprenylindole dimer) is converted into a spirooxindole, containing a strained four-membered ring, which is changed into a spirooxindole isomer with ring expansion on mild acid treatment.