Enantioselective Synthesis of Bispiro[indanedione-oxindole-cyclopropane]s through Organocatalytic [2+1] Cycloaddition

Abstract

A series of compounds featuring a novel bispiro­[indanedione-oxindole-cyclopropane] moiety have been synthesized through a squaramide-catalyzed [2+1] cycloaddition reaction. The tandem Michael-alkylation reaction of 2-arylidene-1,3-indanediones with 3-bromooxindoles furnished the cycloadducts in high yields with excellent diastereo- and enantioselectivities. The ammonium ylide in the catalytic process, as a key intermediate, was revealed by the high-resolution mass spectrometry study.

Diverse synthesis of functionalized hydroquinoline derivatives from α-aryl vinylsulfonium salts

“…13 Chemists are increasingly focused on developing effective strategies for constructing spiro-cyclopropane-oxindoles. 14 In this context, we attempted to achieve the construction of a spiro-cyclopropane-oxindole-fused tetrahydroquinoline structural motif through the reaction between α-phenyl vinylsulfonium tetraphenylborate 1a and 3-(2-aminobenzylidene)oxindole 5a under similar reaction conditions (Scheme 4). Fortunately, the reaction afforded product 6a in 99% yield.…”

Reversal of enantioselectivity in cobalt(ii)-catalyzed asymmetric Michael–alkylation reactions: synthesis of spiro-cyclopropane-oxindoles

“…The construction of an optically active spiro-cyclopropane skeleton is particularly challenging owing to the presence of three contiguous stereocenters in the highly strained three-membered ring. Among the synthetic strategies for preparing these skeletons, 4–7 asymmetric Michael–alkylation reaction of 3-chlorooxindoles with Michael acceptors is one of the most powerful methodologies. In 2012, Kanger and co-workers first utilized the dual nucleophilic/electrophilic character of C-3 at 3-chlorooxindoles in asymmetric Michael–alkylation reaction.…”

Synthesis of Bisspiro(oxindole)s by DMAP‐Catalyzed [3+2] Annulation of Isatin‐Derived Morita‐Baylis‐Hillman Carbonates

“…Researchers have ingeniously crafted a diverse array of such compounds through a series of spirocyclization reactions, such as [2+1], [4] [2+2], [5] [3+2], [6] [3+3], [7] and [4+3] [8] cyclization protocols, from which a number of molecules with potential therapeutic applications have been identified. Yet, the literature on spirooxindole structures predominantly documented mono‐spiro systems, [1,9] with a relative scarcity of reports on their bis‐spiro counterparts [4a,6,10] . Given the intriguing antitumor [11] and antitubercular [10b] activities exhibited by bisspiro(oxindole) structures (Figure 1), the paucity of synthetic reports for these molecules poses a significant obstacle to further biological exploration.…”