Showing papers by "Venkitasamy Kesavan published in 2014"
TL;DR: First asymmetric decarboxylative cyanomethylation of isatins is reported herewith using bifunctional thiourea derived from l-proline in good yields and enantioselectivities.
Abstract: First asymmetric decarboxylative cyanomethylation of isatins is reported herewith using bifunctional thiourea derived from L-proline in good yields and enantioselectivities. This strategy enables the construction of various 3-cyanomethylene substituted 3-hydroxyoxindoles in enantioselective manner. Enantioselective synthesis of CPC-1 alkaloid has been accomplished in fewer steps.
31 citations
TL;DR: In this paper, a new class of bifunctional tertiary amine thiourea was synthesized from l -proline, which is amenable to steric and electronic modifications at the stereogenic center bearing a thioupine moiety.
Abstract: 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.
28 citations
TL;DR: The scope of the current methodology was further extended for the synthesis of C4-, C7-aryl-substituted 1-naphthyl acetamides in good yields and a biologically active dihydro[a]benzocarbazole scaffold was synthesized using the established protocol.
Abstract: Copper(I) bromide catalyzed direct C–H arylation of cyclic enamides was achieved using diaryliodonium salts in the absence of base/additive at ambient temperature with high yields. A biologically active dihydro[a]benzocarbazole scaffold was synthesized using the established protocol. The scope of the current methodology was further extended for the synthesis of C4-, C7-aryl-substituted 1-naphthyl acetamides in good yields.
25 citations
TL;DR: Chiral Lewis bases facilitated the synthesis of highly functionalized spirooxindoles containing α-exo-methylene-γ-butyrolactones in high yields and excellent enantioselectivities at ambient temperature.
23 citations
TL;DR: Tartrate-derived bioxazoline ligands, which form a five-membered chelate ring with metals, were evaluated for use in the asymmetric allylic alkylation (AAA) reactions of various symmetrical and unsymmetrical allyl acetates as discussed by the authors.
11 citations
4 citations
TL;DR: In this paper, the authors used Sc(III)-inda-pybox as a catalytic enanti-lective synthesis of 2,3-dihydroquinazolinones.
Abstract: Derivatives of 2,3-dihydroquinazolinones (2,3-DHQZs) are prized for their prevalent pharmaceutical applications. Although there are potential applications, methods available for the enantioselective synthesis of these valuable compounds are scarce, since the chiral aminal center is prone to racemization. We have overcome the difficulties in the catalytic enantioselective synthesis of 2,3-DHQZs using Sc(III)–inda-pybox as a catalyst, in a process with a broad substrate scope.
3 citations
TL;DR: Tartaric acid derived bidentate bisoxazoline ligands are applied as catalysts for the NFSI promoted enantioselective fluorination of β-keto esters as discussed by the authors.
Abstract: Tartaric acid derived bidentate bisoxazoline ligands are applied as catalysts for the NFSI promoted enantioselective fluorination of β-keto esters (I).
2 citations
TL;DR: Excellent enantioselectivities are obtained in the Michael addition of 1,3-dicarbonyl compounds to nitroolefins using a novel bifunctional thiourea catalyst.
Abstract: Excellent enantioselectivities are obtained in the Michael addition of 1,3-dicarbonyl compounds to nitroolefins using a novel bifunctional thiourea catalyst.
1 citations
TL;DR: The bisoxazoline (BOX) is found to be an efficient ligand in Pd-catalyzed asymmetric allylic alkylation.
Abstract: The bisoxazoline (BOX) is found to be an efficient ligand in Pd-catalyzed asymmetric allylic alkylation.
TL;DR: In this article, the first asymmetric decarboxylative cyanomethylation of isatins was reported using bifunctional thiourea derived from L-proline in good yields and enantioselectivities.
Abstract: First asymmetric decarboxylative cyanomethylation of isatins is reported herewith using bifunctional thiourea derived from L-proline in good yields and enantioselectivities. This strategy enables the construction of various 3-cyanomethylene substituted 3-hydroxyoxindoles in enantioselective manner. Enantioselective synthesis of CPC-1 alkaloid has been accomplished in fewer steps.