Construction of spiro[indoline]oxindoles through one-pot thermal-induced [3+2] cycloaddition/silica gel-promoted fragmentation sequence between isatin ketonitrones and electron-deficient alkynes

Synthesis of functionalized 3,2′-pyrrolidinyl spirooxindoles via domino 1,6-addition/annulation reactions of para-quinone methides and 3-chlorooxindoles

A highly efficient diastereoselective [4 + 1] cycloaddition of ortho-tosylaminophenyl-substituted p-QMs with 3-chlorooxindoles has been developed to afford 3,2′-pyrrolidinyl spirooxindoles.

Regioselectivity and diastereoselectivity of three-component reaction of α-amino acid, dialkyl acetylenedicarboxylates and 2-arylidene-1,3-indanediones

The 1,3-dipolar cycloaddition of active azomethine ylide, which were generated in situ from addition reaction of α-amino acids with dialkyl acetylenedicarboxylates, with 2-arylidene-1,3-indanediones showed versatile regioselectivity and diastereoselectivity. The reaction of sarcosine and glycine afforded one kind of functionalized spiro[indene-2,3'-pyrrolidines]. The other primary α-amino acids such as alanine, phenylalanine and leucine gave another kind of regioisomeric spiro[indene-2,3'-pyrrolidines]. The cyclic α-amino acids resulted in the corresponding spiro[indene-2,2'-pyrrolizines] and [indene-2,6'-pyrrolo[1,2-c]thiazoles].

Synthesis of 2,3′-spirobi[indolin]-2-ones enabled by a tandem nucleophilic benzylation/C(sp2)–N cross-coupling reaction sequence

This study provides an efficient strategy for the construction of spiro[pyrrolidin-3,2′-oxindoles] and represents a new perspective for the synthesis of spirocyclic oxindoles.

An enantioselective synthesis of spiro-oxindole-based 3,4-dihydropyrroles via a Michael/cyclization cascade of 3-aminooxindoles with 2-enoylpyridines

This work provides a highly stereoselective route to access spiro[pyrrolidin-3,2′-oxindoles] and represents a new perspective for the synthesis of spirocyclic oxindoles.

Co-catalysis between DABCO and a Brønsted acid in the catalytic [4 + 2] annulation of isatin with but-3-yn-2-one and mechanistic investigations

Catalytic amounts of the base catalyst DABCO in cooperation with a proton source afford the [4 + 2] cycloadducts of isatins with but-3-yn-2-one in moderate to good yields. Moreover, related plausible mechanisms have been proposed in detail based on control and deuterium labeling experiments.

Four-component reaction of N-alkylimidazoles(N-alkylbenzimidazoles), dialkyl but-2-ynedioate, N-alkylisatins and malononitrile

Convenient synthesis of complex spirooxindolesviafour-component reactions ofN-alkylimidazoles(N-alkylbenzimidazoles), dialkyl but-2-ynedioate,N-alkylisatins and malononitrile.