Tosylhydrazine-promoted self-conjugate reduction–Michael/aldol reaction of 3-phenacylideneoxindoles towards dispirocyclopentanebisoxindole derivatives

• Sayan Pramanik and
• Chhanda Mukhopadhyay

Beilstein J. Org. Chem. 2022, 18, 469–478, doi:10.3762/bjoc.18.49

• and operational simplicity through one pot reaction. Keywords: chemoselective conjugate reduction; dispirocyclopentanebisoxindole scaffolds; metal-free; one-pot operation; reductive cyclization; Introduction There is a vast demand of the structurally complex spirooxindole scaffold which is an

• important functional group transformation for the synthesis of heterocyclic and carbocyclic building blocks and reactive intermediates. Besides the use of various reducing agents, it is observed that tosylhydrazine develops the transition-metal-free and highly chemoselective conjugate reduction of α,β