Highly efficient synthesis of spiro[oxazolidine-2-thione-oxindoles] with 3-isothiocyanato oxindoles and aldehydes via an organocatalytic cascade aldol-cyclization reaction

Metal-Free One-Pot Domino Synthesis of Oxazolidinethione Derivatives of Quaternary Amino Acids from α-Amino Esters and Aldehydes Using CS2

We present a streamlined, metal-free, one-pot domino approach to efficiently synthesize oxazolidinethione derivatives containing substituted quaternary amino acids. This method employs α-amino esters, aldehydes, and CS2 under mild conditions, constructing three new bonds (C-N, C-C, and C-O) to produce oxazolidinethione compounds featuring a quaternary center and a beta-hydroxy derivative in high yields. This scalable protocol enables the creation of libraries of biologically significant, intricate amino acid derivatives using amino esters and aldehydes.

Double Spirocyclization of Arylidene-Δ2-Pyrrolin-4-Ones with 3-Isothiocyanato Oxindoles

Arylidene-Δ2-pyrrolin-4-ones undergo organocatalyzed double spirocyclization with 3-isothiocianato oxindoles in a domino 1,4/1,2-addition sequence. The products contain three contiguous stereocenters (ee up to 98%, dr up to 99:1, 12 examples). The absolute configuration of the major diastereomer was determined by single crystal X-ray analysis. Along with heterocyclic Michael acceptors based on oxazolone, isoxazolone, thiazolidinone, pyrazolone, and pyrimidinedione, the reported results display the applicability of unsaturated Δ2-pyrrolin-4-ones (pyrrolones) for the organocatalyzed construction of 3D-rich pyrrolone-containing heterocycles.

The reaction of arylmethyl isocyanides and arylmethylamines with xanthate esters: a facile and unexpected synthesis of carbamothioates

An unexpected formation of carbamothioates by a sodium hydride-mediated reaction of arylmethyl isocyanides with xanthate esters in DMF is reported. The products thus obtained were compared with the carbamothioates obtained by the sodium hydride-mediated condensation of the corresponding benzylamines and xanthate esters in DMF. To account for these unexpected reactions, a mechanism is proposed in which the key steps are supported by quantum chemical calculations.

Organocatalytic synthesis of enantioenriched 1,2,4-triazolines containing a chiral quaternary carbon center

A tertiary amine catalyzed asymmetric cyclization of isothiocyanates and azodicarboxylates towards the synthesis of chiral 1,2,4-triazolines has been described.

Enantioselective Synthesis of Spirooxindole Enols: Regioselective and Asymmetric [3+2] Cyclization of 3-Isothiocyanato Oxindoles with Dibenzylidene Ketones

A novel cinchona-alkaloid-derived organocatalyst has been developed to catalyze the asymmetric regioselective [3+2] cycloaddition of 3-isothiocyanato oxindoles with dibenzylidene ketones. A series of spirooxindole enols could be obtained in high yields with good-to-excellent diastereo- and enantioselectivities.

Facile construction of novel imidazolidine-spirooxindoles via diastereoselective cycloaddition of N-acylhydrazine-derived imines with 3-isothiocyanato oxindoles

Diastereoselective cycloaddition of N-acylhydrazine-derived imines with 3-isothiocyanato oxindoles forming novel imidazolidine-spirooxindoles.

A Mannich/cyclization cascade process for the asymmetric synthesis of spirocyclic thioimidazolidineoxindoles

An asymmetric cascade Mannich/cyclization reaction between 3-isothiocyanato-oxindoles and sulfimides has been developed for the synthesis of spirocyclic thioimidazolidineoxindoles.

Organocatalytic domino Michael/cyclization reaction: efficient synthesis of multi-functionalized tetracyclic spirooxindoles with multiple stereocenters

A series of chiral multi-functionalized tetracyclic spiro[chromeno[3,4-c]pyrrole-1,3′-indoline] derivatives with four vicinal chiral carbon centers including two quaternary stereocenters were successfully preparedviadomino reaction of various 3-nitro-2H-chromene derivatives to 3-isothiocyanato oxindole with moderate to good enantioselectivities, employing readily available bifunctional thiourea1das the organocatalyst.