Browse
Submit Data
Databases
API
Help

Dataset Information

27 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Thiourea-catalyzed enantioselective addition of indoles to pyrones: alkaloid cores with quaternary carbons.

ABSTRACT: We report the development of a catalytic method for the enantioselective addition of indoles to pyrone-derived electrophiles. Arylpyrrolidino-derived thioureas catalyze the addition with high stereoselectivity in the presence of catalytic quantities of an achiral Brønsted acid. The indole-pyrone adducts feature a quaternary stereocenter and represent an unusual class of indolines bearing structural resemblance to the hybrid natural product pleiocarpamine.

SUBMITTER: Yeung CS

PROVIDER: S-EPMC4235369 | biostudies-literature | 2014 Oct

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Publications

Thiourea-catalyzed enantioselective addition of indoles to pyrones: alkaloid cores with quaternary carbons.

Yeung Charles S CS Ziegler Robert E RE Porco John A JA Jacobsen Eric N EN

Journal of the American Chemical Society 20140917 39

We report the development of a catalytic method for the enantioselective addition of indoles to pyrone-derived electrophiles. Arylpyrrolidino-derived thioureas catalyze the addition with high stereoselectivity in the presence of catalytic quantities of an achiral Brønsted acid. The indole-pyrone adducts feature a quaternary stereocenter and represent an unusual class of indolines bearing structural resemblance to the hybrid natural product pleiocarpamine. ...[more]

PMID: 25213353

Similar Datasets

Enantioselective, thiourea-catalyzed intermolecular addition of indoles to cyclic N-acyl iminium ions.

Project description: Not available

| S-EPMC2803312 | biostudies-literature

Enantioselective thiourea-catalyzed cationic polycyclizations.

Project description:A new thiourea catalyst is reported for the enantioselective cationic polycyclization of hydroxylactams. Both the yield and enantioselectivity of this transformation were found to vary strongly with the identity of a single aromatic residue on a common catalyst framework, with more expansive and polarizable arenes proving optimal. Evidence is presented for a mechanism in which stabilizing cation-pi interactions are a principal determinant of enantioselectivity.

| S-EPMC2989498 | biostudies-literature

Regio- and enantioselective synthesis of acyclic quaternary carbons via organocatalytic addition of organoborates to (Z)-Enediketones.

Project description:The chemical synthesis of molecules with closely packed atoms having their bond coordination saturated is a challenge to synthetic chemists, especially when three-dimensional control is required. The organocatalyzed asymmetric synthesis of acyclic alkenylated, alkynylated and heteroarylated quaternary carbon stereocenters via 1,4-conjugate addition is here catalyzed by 3,3´-bisperfluorotoluyl-BINOL. The highly useful products (31 examples) are produced in up to 99% yield and 97:3 er using enediketone substrates and potassium trifluoroorganoborate nucleophiles. In addition, mechanistic experiments show that the (Z)-isomer is the reactive form, ketone rotation at the site of bond formation is needed for enantioselectivity, and quaternary carbon formation is favored over tertiary. Density functional theory-based calculations show that reactivity and selectivity depend on a key n→π* donation by the unbound ketone's oxygen lone pair to the boronate-coordinated ketone in a 5-exo-trig cyclic ouroboros transition state. Transformations of the conjugate addition products to key quaternary carbon-bearing synthetic building blocks proceed in good yield.

| S-EPMC10787796 | biostudies-literature

Thiourea-catalyzed enantioselective cyanosilylation of ketones.

Project description:The new chiral amino thiourea catalyst 3d promotes the highly enantioselective cyanosilylation of a wide variety of ketones. The hindered tertiary amine substituent plays a crucial role with regard to both stereoinduction and reactivity, suggesting a cooperative mechanism involving electrophile activation by thiourea and nucleophile activation by the amine.

| S-EPMC3166885 | biostudies-literature

Enantioselective thiourea-catalyzed additions to oxocarbenium ions.

Project description:Asymmetric, catalytic reactions of oxocarbenium ions are reported. Simple, chiral urea and thiourea derivatives are shown to catalyze the enantioselective substitution of silyl ketene acetals onto 1-chloroisochromans. A mechanism involving anion binding by the chiral catalyst to generate a reactive oxocarbenium ion is invoked. Catalysts bearing tertiary benzylic amide groups afforded highest enantioselectivities, with the optimal structure being derived from enantioenriched 2-arylpyrrolidine derivatives.

| S-EPMC2574628 | biostudies-literature

Enantioselective thiourea-catalyzed intramolecular cope-type hydroamination.

Project description:Catalysis of Cope-type rearrangements of bis-homoallylic hydroxylamines is demonstrated using chiral thiourea derivatives. This formal intramolecular hydroamination reaction provides access to highly enantioenriched ?-substituted pyrrolidine products and represents a complementary approach to metal-catalyzed methods.

| S-EPMC3689223 | biostudies-literature

Thiourea-catalyzed enantioselective iso-Pictet-Spengler reactions.

Project description:A one-pot condensation of isotryptamines and aldehydes that affords enantiomerically enriched 4-substituted tetrahydro-γ-carbolines is reported. The reaction is induced by a chiral thiourea/benzoic acid dual catalyst system. Purification of the N-Boc-protected products by trituration or crystallization provides the optically pure tetrahydro-γ-carboline derivatives in a scalable and highly practical procedure.

| S-EPMC3206290 | biostudies-literature

Copper(II)- and palladium(II)-catalyzed enantioselective Claisen rearrangement of allyloxy- and propargyloxy-indoles to quaternary oxindoles and spirocyclic lactones.

Project description:In this Article, a strategy to obtain highly enantioselective catalysts for the Claisen rearrangement of allyloxy- and propargyloxy-indoles is outlined. Ultimately, copper BOX and palladium BINAP or PHOX catalysts were discovered as superior in catalyzing Claisen rearrangements of allyloxy- or proparyloxy-substituted indoles to generate oxindoles bearing allyl- or allenyl-substituted quaternary centers. This method proved to be tolerant of a broad range of functional groups. Tandem reactions of the silyl-allene products provide rapid access to a variety of spirocyclic oxindoles in one operation.

| S-EPMC3528852 | biostudies-literature

Rhodium(II)-catalyzed enantioselective C-H functionalization of indoles.

Project description:A catalytic, enantioselective method for the C-H functionalization of indoles by diazo compounds has been achieved. With catalytic amounts of Rh(2)(S-NTTL)(4), the putative Rh-carbene intermediates from α-alkyl-α-diazoesters react with indoles at C(3) to provide α-alkyl-α-indolylacetates in high yield and enantioselectivity. From DFT calculations, a mechanism is proposed that involves a Rh-ylide intermediate with oxocarbenium character.

| S-EPMC3144986 | biostudies-literature

Iridium-catalyzed regio- and enantioselective N-allylation of indoles.

Project description: Not available

| S-EPMC2819323 | biostudies-literature