A new synthetic strategy to construct spirooxindole-naphthopyran scaffold has been demonstrated via Friedel-Crafts type/hemiketalization of oxindole α-ketoester with 2-naphthol. Under the established reaction condition, quaternary chiral center at C3-position of oxindole has been created with very good asymmetric induction up to 98 % for a broad range of substrates. DFT calculations, which account for the stereochemical outcome, were performed. © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

M. Michael Gromiha

Department Of Biotechnology

Venkitasamy Kesavan

Subramaniam Muthusamy

Muthuraj Prakash

Chandrasekaran Ramakrishnan

Amino acids

Asymmetric induction

asymmetric synthesis

Enantioselective

Heterocycles

Organocatalysis

Reaction conditions

Spiro compounds

Synthetic strategies

Scaffolds

IIT Madras is a public technical and research university located in Chennai, Tamil Nadu. Founded in 1959, it is recognised as an Institute of National Importance.

IIT Madras has been ranked as the top engineering institute in India for four years in a row by the National Institutional Ranking Framework of the MHRD

It currently offers undergraduate, postgraduate and research degrees across 16 disciplines in Engineering, Sciences, Humanities and Management. About 596 faculty belonging to science and engineering departments and centres of the Institute are engaged in teaching, research and industrial consultancy.

IIT Madras

ChemCatChem

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. © 2018 Elsevier Ltd

Tetrahedron Letters

Efficient synthesis of highly functionalized indole and phenol containing 3,3′-disubstituted oxindoles and chromene fused spirooxindoles

Sequential vinylogous Michael addition-cyclization reactions of vinyl malononitriles with isatylidene malononitrile were accomplished using l-proline derived bifunctional thiourea. Cyclohexylidine malononitrile afforded exclusively the single diastereomer with good to excellent enantioselectivity (up to 99% ee) for diverse oxindole spirocyclohexene derivatives. Tetralone derived α,α-dicyano alkene was also employed to access spirocyclic oxindole scaffolds with an excellent level of stereoselectivity (up to 99% ee). © The Royal Society of Chemistry.

RSC Advances

Enantioselective assembly of functionalized carbocyclic spirooxindoles using an L-proline derived thiourea organocatalyst

Palladium(ii)-catalyzed C3-allylation of 3-ethynyl-3-OBoc oxindole derivatives was achieved for the first time to access highly functionalized 3-allyl-3-ethynyl substituted oxindole derivatives for a broad range of substrates in very good yields (up to 94%). The synthetic applications of the allylated products were explored by synthesizing five and six membered carbocyclic spirooxindoles in moderate to very good diastereoselectivities. © The Royal Society of Chemistry.

Fulltext

Assembly of 3-allyl-3-ethynyl-oxindole motifs via palladium(ii)-catalyzed quaternary allylation of 3-ethynyl-3-OBoc-oxindoles

A new class of bifunctional tertiary amine thiourea was synthesized from l-proline. The reported thiourea is amenable to steric and electronic modifications at the stereogenic center bearing a thiourea moiety. Excellent enantioselectivity was obtained in the Michael addition of 2,4-pentanedione to various nitro olefins using the new organocatalyst. The construction of contiguous stereocenters via the Michael reaction of substituted 1,3-dicarbonyls to nitro olefins was also carried out with very good yield, enantioselectivity, and diastereoselectivity. © 2014 Elsevier Ltd. All rights reserved.

Tetrahedron Asymmetry

New class of bifunctional thioureas from l-proline: Highly enantioselective Michael addition of 1,3-dicarbonyls to nitroolefins

Chemical Communications

Catalytic asymmetric chemoselective 1,3-dipolar cycloadditions of an azomethine ylide with isatin-derived imines: diastereo- and enantioselective construction of a spiro[imidazolidine-2,3′-oxindole] framework

The Journal of Organic Chemistry

Organocatalytic Asymmetric Michael/Cyclization Cascade Reactions of 3-Hydroxyoxindoles/3-Aminooxindoles with α,β-Unsaturated Acyl Phosphonates for the Construction of Spirocyclic Oxindole-γ-lactones/lactams

Organocatalytic Enantioselective Assembly of Spirooxindole-naphthopyrans through Tandem Friedel-Crafts Type/Hemiketalization

Journal	Data powered by TypesetChemCatChem
Publisher	Data powered by TypesetWiley Blackwell
ISSN	18673880
Open Access	No