Asymmetric Reactions of Axially Chiral Amides: Use of Removable Ortho-Substituents in Radical Cyclizations of o-Iodoacrylanilides and N-Allyl-N-o-Iodoacrylamides

Radical cyclizations of enantiomerically enriched o-iodoacrylanilides and N-allyl-o-iodoanilides bearing a removable ortho-substituent such as trimethylsilyl or bromine provide oxindoles and indoles in good yields and with good to excellent levels of chirality transfer from the N–Ar axis to the new stereocenter. Transition state models for the chirality transfer are suggested. Chemoselectivity of the radical cyclization in favor of the iodine in the case of 2-iodo-6-bromo-N-allylacrylamides has been exploited for the synthesis of chiral pyrroloquinolinones by a one-pot sequence of 5-exo and 6-endo cyclizations