Chameleon-Like Activating Nature of the Spirooxindole Group in Donor–Acceptor Cyclopropanes

Abstract

The concept of a chameleon activating group is considered in the context of donor–acceptor cyclopropane chemistry. When spiro-conjugated with cyclopropane, oxindole can act as an acceptor or a donor depending on the electronic nature of vicinal substituents. This dichotomy is reflected in the alteration of chemoselectivity of spiro­[oxindole-1,3′-cyclopropane] ring opening with nucleophiles.

Additive‐Free Synthesis of Trifluoromethylated Spiro Cyclopropanes and Their Transformation into Trifluoromethylated Building Blocks

“…In addition to the inherent potential these spiro TFCps possess, the presence of donor and acceptor groups make them promising candidates for assembling valuable synthetic building blocks either through the ring expansion or ring opening reactions. [12] Drawing inspiration from the well-known annulations of spiro cyclopropanes, [13] we envisioned that an appropriate dipolarophile would take part in the ring expansive annulation reaction under Lewis acid conditions.…”

Stereoselective synthesis and applications of spirocyclic oxindoles

“…in ring opening reactions. 17 These ring opening reactions can often be coupled with ring closing reactions to form spirocycles of larger ring size. There has recently been an excellent review on the catalytic enantioselective synthesis of polysubstituted spirocyclopropyl oxindoles by Cao and Zhou, 18 as well as a review of transition metal-free strategies by Ashfeld.…”

Syntheses and Applications of Spirocyclopropyl Oxindoles: A Decade Review

“…Recently, Budynina and co‐workers disclosed chameleon‐like activating behaviour of spirocyclopropyl oxindoles. [ 67 ] Herein, a switch in typical activating nature of spirocyclopropane was observed based on electronic effect of the substituents. This dichotomy in alteration of chemoselectivity of spiro cyclopropyl oxindoles was tested by two model nucleophiles (azide and amine).…”