Allylation and alkylation of oxindoleketimines via imine umpolung strategy

When treated with an alkoxide base like t-BuOK in aprotic solvent, N-diphenylmethyl imino oxindoles, made conveniently through condensation of corresponding isatins with N-diphenylmethyl amine, are deprotonated to form azaallyl anions. Allylation and alkylation of this type of intermediates proceed smoothly with diverse C-electrophiles. Acidic work up finishes 3-amino-3-allyl/alkyl oxindoles. The overall transformation equals to an umpolung process at the C3 of isatins. (c) 2021 Chinese Chemical Society and Institute of Materia Medica, Chinese Academy of Medical Sciences. Published by Elsevier B.V. All rights reserved.

Automated summary

By treating N-diphenylmethyl imino oxindoles with alkoxide bases in aprotic solvents, azaallyl anions can be formed through deprotonation, allowing for smooth allylation and alkylation with various C-electrophiles. The final acidic workup yields 3-amino-3-allyl/alkyl oxindoles, representing an umpolung process at the C3 of isatins.