horsfiline and 2-oxindole

The first enantioselective total syntheses of architecturally interesting prenylated pyrroloindole alkaloids, (-)-pseudophrynamines 272A (3d) and 270 (3b), have been achieved starting from enantioenriched 2-oxindoles having all-carbon quaternary stereocenters. A common strategy involving a thio-urea catalyzed aldol reaction is employed for the total synthesis of both spiro(pyrrolidinyl-oxindole) and hexahydropyrrolo[2,3-b]indole alkaloids.

Topics: Aldehydes; Aniline Compounds; Catalysis; Indole Alkaloids; Indoles; Molecular Structure; Oxindoles; Physostigmine; Prenylation; Spiro Compounds; Stereoisomerism

The series of 3-monofunctionalized 2-oxindoles 2 were conveniently synthesized from reactions between anilide 1 and phenyliodine(III) diacetate (PIDA) through hypervalent iodine mediated C(sp2)–C(sp2) bond formation followed by a subsequent deacylation reaction. This metal-free method, shown to provide direct access to an important oxindole intermediate, could be applied to the total synthesis of naturally occurring horsfiline.

Topics: Catalysis; Indoles; Iodobenzenes; Metals; Molecular Structure; Oxidation-Reduction; Oxindoles; Spiro Compounds

An efficient and novel procedure for a copper catalyzed domino coupling reaction has been developed, which afforded various oxindoles in good to excellent yields with tolerance of various substituents. In addition, this method could be applied to synthesize horsfiline and coerulescine in few steps with high total yields.

Topics: Aniline Compounds; Catalysis; Copper; Indoles; Oxindoles; Spiro Compounds

Expedient routes to three classes of novel spiro-fused pyrrolidine, piperidine, and indoline heterocycle scaffolds are described. These three-dimensional frameworks, which conform to the "rule of three", are suitably protected to allow for site-selective manipulation and functionalization. Different modes of substrate control were explored, which allow for good to excellent levels of diastereoselectivity and dispense with the need for additional chiral reagents or catalysts. The concepts developed were applied in short, formal syntheses of (±)-coerulescine and (±)-horsfiline.

Topics: Aniline Compounds; Catalysis; Indoles; Lactams; Molecular Structure; Oxindoles; Piperidines; Pyrrolidines; Spiro Compounds; Stereoisomerism

The preparation of 3,3-disubstituted oxindoles by a formal C-H, Ar-H coupling of anilides is described. Highly efficient conditions have been identified using catalytic (5 mol %) Cu(OAc)(2).H(2)O with atmospheric oxygen as the reoxidant; no additional base is required, and the reaction can be run in toluene or mesitylene. Optimization studies are reported together with a scope and limitation investigation based on variation of the anilide precursors. The application of this methodology to prepare a key intermediate for the total synthesis of the anticancer, analgesic oxindole alkaloid Horsfiline is also described.

Topics: Anilides; Catalysis; Copper; Indoles; Molecular Structure; Oxidation-Reduction; Oxindoles; Spiro Compounds