Browse
Submit Data
Databases
API
Help

Dataset Information

5 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Reagent-controlled regiodivergent intermolecular cyclization of 2-aminobenzothiazoles with ?-ketoesters and ?-ketoamides.

ABSTRACT: Two regiodivergent approaches to intermolecular cyclization of 2-aminobenzothiazoles with ?-ketoesters and amides have been developed, controlled by the reagents employed. With the Brønsted base KOt-Bu and CBrCl3 as radical initiator, benzo[d]imidazo[2,1-b]thiazoles are synthesized via attack at the ?-carbon and keto carbon of the ?-ketoester moiety. In contrast, switching to the Lewis acid catalyst, In(OTf)3, results in the regioselective nucleophilic attack at both carbonyl groups forming benzo[4,5]thiazolo[3,2-a]pyrimidin-4-ones instead.

SUBMITTER: Roslan II

PROVIDER: S-EPMC5753174 | biostudies-literature | 2017

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Publications

Reagent-controlled regiodivergent intermolecular cyclization of 2-aminobenzothiazoles with β-ketoesters and β-ketoamides.

Roslan Irwan Iskandar II Ng Kian-Hong KH Chuah Gaik-Khuan GK Jaenicke Stephan S

Beilstein journal of organic chemistry 20171218

Two regiodivergent approaches to intermolecular cyclization of 2-aminobenzothiazoles with β-ketoesters and amides have been developed, controlled by the reagents employed. With the Brønsted base KOt-Bu and CBrCl3 as radical initiator, benzo[d]imidazo[2,1-b]thiazoles are synthesized via attack at the α-carbon and keto carbon of the β-ketoester moiety. In contrast, switching to the Lewis acid catalyst, In(OTf)3, results in the regioselective nucleophilic ...[more]

PMID: 29564009

Similar Datasets

Reagent-controlled regiodivergent ring expansions of steroids.

Project description:Ring expansion provides a powerful way of introducing a heteroatom substituent into a carbocyclic framework. However, such reactions are often limited by the tendency of a given substrate to afford only one of the two rearrangement products or fail to achieve high selectivity at all. These limitations are particularly acute when seeking to carry out late-stage functionalization of natural products as starting points in drug discovery. In this work, we present a stereoelectronically controlled ring expansion sequence towards selective and flexible access to complementary ring systems derived from common steroidal substrates. Chemical diversification of the reaction intermediate affords over 100 isomerically pure analogs with spatial and functional diversity. This regiodivergent rearrangement, and the concept of using chiral reagents to affect regiocontrol in chiral natural products, should be broadly applicable to late-stage natural product diversification programs.

| S-EPMC5838248 | biostudies-other

Enantio- and diastereoselective intermolecular Stetter reaction of glyoxamide and alkylidene ketoamides.

Project description:A triazolinylidene carbene catalyzed intermolecular Stetter reaction of glyoxamide and alkylidene ketoamides has been developed. 1,4-Dicarbonyl products are afforded in good to excellent yields, enantioselectivities, and diastereoselectivities. Further derivatization of the products affords useful intermediates for organic synthesis.

| S-EPMC2782595 | biostudies-literature

Rh(I)-catalyzed intermolecular hydroacylation: enantioselective cross-coupling of aldehydes and ketoamides.

Project description:Under Rh(I) catalysis, ?-ketoamides undergo intermolecular hydroacylation with aliphatic aldehydes. A newly designed Josiphos ligand enables access to ?-acyloxyamides with high atom-economy and enantioselectivity. On the basis of mechanistic and kinetic studies, we propose a pathway in which rhodium plays a dual role in activating the aldehyde for cross-coupling. A stereochemical model is provided to rationalize the sense of enantioinduction observed.

| S-EPMC4091274 | biostudies-literature

Chiral Hypervalent Iodine Catalysis Enables an Unusual Regiodivergent Intermolecular Olefin Aminooxygenation.

Project description:A novel iodide-catalyzed intermolecular aminooxygenation strategy is described here. Amide is used as the O- and N- source to probe for regiocontrol strategies. Notably, simple additives can be selectively introduced to achieve regiodivergent oxyamination processes for electronically activated alkenes while being regio-complementary for unactivated alkenes. Our preliminary data demonstrates that this regiocontrol strategy based on nucleophile can also be applied in asymmetric processes using chiral hypervalent iodine catalysis.

| S-EPMC8243328 | biostudies-literature

Catalyst Controlled Regiodivergent Arylboration of Dienes.

Project description:A method for the regiodivergent arylboration of dienes is presented. These reactions allow for the formation of a diverse range of synthetically versatile products from simple precursors. Through mechanistic studies, these reactions likely operate by initial addition of a Cu-Bpin complex across the diene followed by Pd-catalyzed cross coupling with an aryl halide or pseudohalide.

| S-EPMC5618444 | biostudies-literature

Hypervalent iodine(III)-promoted intermolecular C-C coupling of vindoline with ?-ketoesters and related substrates.

Project description:The regioselective intermolecular coupling reaction of vindoline with a wide range of substrates including ?-ketoesters, ?-diketones, ?-ketoaldehydes, ?-ketonitriles, malononitriles, and ?-cyanoesters provides an opportunity for the synthesis of vinblastine analogues containing deep-seated changes in the upper velbanamine subunit. The transition-metal-free hypervalent iodine(III)-promoted intermolecular sp(3)/sp(2) coupling, representing a special class of selective C-H activation with direct carbon-carbon bond formation, proceeds with generation of a quaternary center capable of incorporation of the vinblastine C16' methyl ester and functionalized for subsequent divergent heterocycle introduction.

| S-EPMC3607625 | biostudies-literature

Ligand-Controlled Regiodivergent Enantioselective Rhodium-Catalyzed Alkene Hydroboration.

Project description:Regiocontrol in the rhodium-catalyzed boration of vinyl arenes is typically dominated by the presence of the conjugated aryl substituent. However, small differences in TADDOL-derived chiral monophosphite ligands can override this effect and direct rhodium-catalyzed hydroboration of ?-aryl and ?-heteroaryl methylidenes by pinacolborane to selectively produce either chiral primary or tertiary borated products. The regiodivergent behavior is coupled with enantiodivergent addition of the borane. The nature of the TADDOL backbone substituents and that of the phosphite moiety function synergistically to direct the sense and extent of regioselectivity and enantioinduction. Twenty substrates are shown to undergo each reaction mode with regioselectivity values reaching greater than 20:1 and enantiomer ratios reaching up to 98:2. A variety of subsequent transformations illustrate the potential utility of each product.

| S-EPMC6663592 | biostudies-literature

Catalyst-Controlled Regiodivergent C-H Alkynylation of Thiophenes*.

Project description:Alkynes are highly attractive motifs in organic synthesis due to their presence in natural products and bioactive molecules as well as their versatility in a plethora of subsequent transformations. A common procedure to insert alkynes into (hetero)arenes, such as the thiophenes studied herein, consists of a halogenation followed by a Sonogashira cross-coupling. The regioselectivity of this approach depends entirely on the halogenation step. Similarly, direct alkynylations of thiophenes have been described that follow the same regioselectivity patterns. Herein we report the development of a palladium catalyzed C-H activation/alkynylation of thiophenes. The method is applicable to a broad range of thiophene substrates. For 3-substituted substrates where controlling the regioselectivity between the C2 and C5 position is particularly challenging, two sets of reaction conditions enable a regiodivergent reaction, giving access to each regioisomer selectively. Both protocols use the thiophene as limiting reagent and show a broad scope, rendering our method suitable for late-stage modification.

| S-EPMC7839547 | biostudies-literature

Ligand Controlled Ir-Catalyzed Regiodivergent Oxyamination of Unactivated Alkenes.

Project description:An intramolecular Ir(III)-catalyzed regiodivergent oxyamination of unactivated alkenes provides valuable ?-lactams, ?-lactones and ?-lactams. The regioselectivity is controlled by the electronically tunable cyclopentadienyl Ir(III)-complexes enabling oxyamination via either 5-exo or 6-endo pathways. With respect to the mechanism, we propose a highly reactive [3.1.0] bicycle intermediate derived from Ir(V) nitrene-mediated aziridination to be a key intermediate toward the synthesis of ?-lactams.

| S-EPMC6980349 | biostudies-literature

A(1,3)-strain enabled retention of chirality during bis-cyclization of beta-ketoamides: total synthesis of (-)-salinosporamide A and (-)-homosalinosporamide A.

Project description:A concise, enantioselective synthesis of the Phase I anticancer agent, (-)-salinosporamide A, is described. The brevity of the described strategy stems from a key bis-cyclization of a beta-keto tertiary amide, accomplished on gram scale, which retains optical purity enabled by A(1,3)-strain rendering epimerization slow relative to the rate of bis-cyclization. The versatility of the strategy for derivative synthesis is demonstrated by the synthesis of (-)-homosalinosporamide A.

| S-EPMC2981177 | biostudies-other

OmicsDI is part of the ELIXIR infrastructure

OmicsDI is an Elixir interoperability service. Learn more ›

OmicsDI Databases

PRIDE
PeptideAtlas
MassIVE
JPOST Repository
Physiome Model Repository

EGA
EVA
ENA
LINCS
PAXDB
Cell Collective

MetaboLights
Metabolomics Workbench
MetabolomeExpress
GNPS
BioModels
FAIRDOMHub

ArrayExpress
dbGaP
ExpressionAtlas
GEO
NODE

Information

Databases
Help
API
Contact us
Code on GitHub
Terms of use
Submit Data