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Enantioselective construction of bioinspired coumarin and oxindole hybrid structures always enduring challenges in organic chemistry due to the generation of asymmetric quaternary/spiro center at the C3 position of oxindole. Herein, we demonstrated a facile enantioselective synthesis of highly functionalized 3,3'‐disubstituted oxindole derivatives containing 3‐acetyl coumarins and pyranocoumarin fused spirooxindoles using L‐proline derived bifunctional thiourea organocatalyst through Aldol reaction and Michael addition/cyclization. The L‐proline derived thiourea catalyst well performed with broad substrate scope to produce desired products in very good yields (up to 95 %) and excellent enantioselectivities (up to 99 % ee). [ABSTRACT FROM AUTHOR]

An asymmetric [3 + 2] formal cycloaddition reaction between oxindole α‐keto esters and enals has been developed. This α,γ‐regioselective reaction afforded multifunctional carbocyclic oxindoles via dienamine‐enamine cascade reaction followed by isomerization. Furthermore, a highly enantioselective Diels‐Alder reaction was demonstrated between 2,4‐dienals and oxindole α‐keto esters via trienamine intermediates. Chiral secondary amine catalyzed the both reactions under mild conditions and the cyclized products were isolated in moderate to good yields with good diastereoselectivities (>20:1 dr) and enantioselectivities (up to 99 %). [ABSTRACT FROM AUTHOR]

3-Alkynyl-3-OBoc (Boc = tert-butoxycarbonyl) oxindole derivatives underwent a CuII-mediated stereo- and regioselective Friedel-Crafts alkylation/5- exo- dig-cyclization with 2-naphthols or cyclic 1,3-diketones. This gave spirooxindole [2,1- b]furan motifs in good to excellent yields under ambient conditions, and the process has a wide substrate scope. [ABSTRACT FROM AUTHOR]

The first thiourea catalysed asymmetric [3+2] cycloaddition reaction between azomethine imines and malanonitriles was developed. Using this novel synthetic strategy, hybrid molecules containing N,N-bicyclic pyrazolidinones fused with enaminonitriles were synthesized in good yields with excellent enantioselectivities (up to 98% ee). [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Efficient strategy to access biologically important 3,3-disubstituted Oxindoles. • Excellent functional group tolerance and wide substrate scope. • Metal-free intramolecular iodocyclization to enable chromene fused spirooxindoles. • Diverse 3,3-disubstitued and chromene fused spirooxindoles in high yields. Abstract 3-Alkynyl-3-OBoc oxindoles underwent Cu(II) mediated Friedel-Crafts alkylation with indoles and phenols to yield of structurally diverse 3-alkynyl-3-indole/phenol-oxindole derivatives. The synthetic application of alkylated phenol derivatives were further demonstrated to biologically important new class of chromene fused spirooxindoles through intramolecular metal-free iodocyclization under mild reaction conditions with broad substrate scope in very good yields. [ABSTRACT FROM AUTHOR]

Oxidation reactions are significant transformations used extensively in chemical production. Use of molecular oxygen as an oxidant is certainly environmental friendly and adds to the greenness of the process. A number of metal catalysts have been developed for aerobic oxidation. This digest summarizes the recent advances in aerobic oxidation reactions using ruthenium catalysts for various transformations such as C–H activation/cyclization, alkyne/alkene oxidation, and oxidation of alcohols and amines. [ABSTRACT FROM AUTHOR]

[Display omitted] • Efficient asymmetric allylic alkylation (AAA) strategy to access chiral 3-allyl-3-amino-2-oxindoles. • Tartrate derived bi(oxazoline)-palladium (II) induce the asymmetric induction. • 3-Amino-2-oxindoles used as prochiral nucleophile. • Metal-free intramolecular iodocyclization to enable chiral spiro-pyrrolidine-2-oxindoles. Tartrate derived bi(oxazoline) ligand with palladium (II) species catalyzed asymmetric allylic alkylation reaction to access highly valuable 3-allyl-3-amino-2-oxindoles with vicinal quaternary and tertiary stereocenters in very good yields (up to 91%) and excellent enantioselectivity (up to 98% ee) with moderate to good diastereoselectivity (up to 5:1). The synthetic utility of 3-allyl-3-amino-2-oxindole was further demonstrated to construct spiro(oxindole-3,2′-pyrrolidine) with consecutive one quaternary and three tertiary chiral centers in good stereoselectivity (dr = 8:1 and 80% ee) through metal-free intramolecular iodocyclization reaction. [ABSTRACT FROM AUTHOR]

The article presents chemical equations related to the article "Enantioselective Synthesis of Spirooxindole α -exo-Methylene-γ -butyrolactones from 3-OBoc-Oxindoles" by S. Jayakumar and others, published in the periodical "European Journal of Organic Chemistry" in 2014.