Browse
Submit Data
Databases
API
Help

Dataset Information

0 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Intramolecular oxamidation of unsaturated O-alkyl hydroxamates: a remarkably versatile entry to hydroxy lactams.

ABSTRACT: The development of a versatile method for the preparation of five- to eight-membered hydroxy lactams that involves the iodine(III)-mediated oxamidation of unsaturated O-alkyl hydroxamates is described. This transformation, which is believed to proceed through the intermediacy of singlet nitrenium and bicyclic N-acyl-N-alkoxyaziridinium ions, is both stereospecific and highly regioselective in most of the 22 cases examined.

SUBMITTER: Wardrop DJ

PROVIDER: S-EPMC2812663 | biostudies-literature | 2010 Feb

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Publications

Intramolecular oxamidation of unsaturated O-alkyl hydroxamates: a remarkably versatile entry to hydroxy lactams.

Wardrop Duncan J DJ Bowen Edward G EG Forslund Raymond E RE Sussman Adam D AD Weerasekera Samanthi L SL

Journal of the American Chemical Society 20100201 4

The development of a versatile method for the preparation of five- to eight-membered hydroxy lactams that involves the iodine(III)-mediated oxamidation of unsaturated O-alkyl hydroxamates is described. This transformation, which is believed to proceed through the intermediacy of singlet nitrenium and bicyclic N-acyl-N-alkoxyaziridinium ions, is both stereospecific and highly regioselective in most of the 22 cases examined. ...[more]

PMID: 19788297

Similar Datasets

A mild and efficient approach to enantioenriched ?-hydroxyethyl ?,?-unsaturated ?-lactams.

Project description:A straightforward approach toward enantioenriched ?-substituted ?,?-unsaturated ?-lactams is described. Although a considerable number of approches toward ?,?-unsaturated ?-lactams have been reported, there are relatively few examples of enantioenriched ?,?-disubstituted ?,?-unsaturated ?-lactams formation. The ?-stereocenter was formed by addition of allylmagnesium bromide to an N-tert-butylsulfinyl imine. The ?,?-unsaturated ?-lactam was furnished by ring-closing metathesis. Although Baylis-Hillman chemistry failed on this cyclic compound, introduction of the hydroxyethyl group prior to ring-closing metathesis was successful. A Baylis-Hillman reaction was used to introduce the substituent at the ?-position of the ?,?-unsaturated lactam.

| S-EPMC4864989 | biostudies-literature

Synthesis of Secondary Unsaturated Lactams via an Aza-Heck Reaction.

Project description:The preparation of unsaturated secondary lactams via the palladium-catalyzed cyclization of O-phenyl hydroxamates onto a pendent alkene is reported. This method provides rapid access to a broad range of lactams that are widely useful building blocks in alkaloid synthesis. Mechanistic studies support an aza-Heck-type pathway.

| S-EPMC5395365 | biostudies-literature

cis-dihydroxylation of unsaturated potassium alkyl- and aryltrifluoroborates.

Project description:[reaction: see text] The cis-dihydroxylation of olefin-containing potassium alkyl- and aryltrifluoroborates proceeds readily in moderate to excellent yields. The resulting diols are efficient coupling partners in Suzuki-Miyaura-type reactions with both alkenyl and aryl bromides.

| S-EPMC2504008 | biostudies-literature

Cobalt-Catalyzed Intramolecular Silylperoxidation of Unsaturated Diisopropylsilyl Ethers.

Project description:A cobalt-catalyzed intramolecular silylperoxidation reaction was developed that allows for the conversion of unsaturated diisopropylsilyl ethers to 3-sila-1,2,4-trioxepanes. Reduction of the peroxide unit of the 3-sila-1,2,4-trioxepane yields six-membered ring diisopropylsilylene acetals.

| S-EPMC7189782 | biostudies-literature

Palladium-Catalyzed Enantioselective Relay Heck Arylation of Enelactams: Accessing ?,?-Unsaturated ?-Lactams.

Project description:In this Communication, we describe the construction of chiral ?,?-unsaturated ?-lactams, widely used as pharmacophores, in high yields and excellent enantioselectivities using an oxidative relay Heck arylation reaction. This strategy also allows facile access to 7-substituted ?,?-unsaturated ?-lactam products and ?-lactams containing a tetrasubstituted nitrogen-bearing stereocenter.

| S-EPMC5993423 | biostudies-other

Proximity effects in nucleophilic addition reactions to medium-bridged twisted lactams: remarkably stable tetrahedral intermediates.

Project description:The reactions of a series of strained bicyclic and tricyclic one-carbon bridged lactams with organometallic reagents have been investigated. These amides permit isolation of a number of remarkably stable hemiaminals upon nucleophilic addition to the twisted amide bonds present in the lactam precursors. The factors that affect the stability of the resulting bridged hemiaminals are presented. In some cases, the hemiaminals were found to collapse to the open-form amino ketones in a manner expected for traditional carboxylic acid derivatives. Transannular N...C=O interactions were also observed in some nine-membered amino ketones. Additionally, tricyclic bridged lactams were found to react with some nucleophiles that typically react with ketones but not with planar amides. The effect of geometry on the reactivity of amide bonds and the amide bond distortion range that marks the boundary of amide-like and ketone-like carbonyl reactivity of lactams are also discussed.

| S-EPMC2820158 | biostudies-literature

Remarkably mild and efficient intramolecular Friedel-Crafts cyclization catalyzed by In(III).

Project description:[structure: see text]. Indium(III) salts were found to be highly effective catalysts for the intramolecular Friedel-Crafts reaction of simple allylic bromides and arenes. In(III) salts appear to be the most general and possess unique halophilic properties as a Lewis acid for this reaction among the catalysts evaluated to date. Deactivated arenes possessing chloride, bromide, and fluoride underwent smooth reaction when activated by InCl3.

| S-EPMC2553353 | biostudies-literature

Cyclic alkyl amino carbene (CAAC) ruthenium complexes as remarkably active catalysts for ethenolysis.

Project description:An expanded family of ruthenium-based metathesis catalysts bearing cyclic alkyl amino carbene (CAAC) ligands was prepared. These catalysts exhibited exceptional activity in the ethenolysis of the seed-oil derivative methyl oleate. In many cases, catalyst turnover numbers (TONs) of more than 100,000 were achieved, at a catalyst loading of only 3?ppm. Remarkably, the most active catalyst system was able to achieve a TON of 340,000, at a catalyst loading of only 1?ppm. This is the first time a series of metathesis catalysts has exhibited such high performance in cross-metathesis reactions employing ethylene gas, with activities sufficient to render ethenolysis applicable to the industrial-scale production of linear ?-olefins (LAOs) and other terminal-olefin products.

| S-EPMC4713124 | biostudies-literature

N-activated ?-lactams as versatile reagents for acyl carrier protein labeling.

Project description:Acyl carrier proteins are critical components of fatty acid and polyketide biosynthesis. Their primary function is to shuttle intermediates between active sites via a covalently bound phosphopantetheine arm. Small molecules capable of acylating this prosthetic group will provide a simple and reversible means of introducing novel functionality onto carrier protein domains. A series of N-activated ?-lactams are prepared to examine site-specific acylation of the phosphopantetheine-thiol. In general, ?-lactams are found to be significantly more reactive than our previously studied ?-lactones. Selectivity for the holo over apo-form of acyl carrier proteins is demonstrated indicating that only the phosphopantetheine-thiol is modified. Incorporation of an N-propargyloxycarbonyl group provides an alkyne handle for conjugation to fluorophores and affinity labels. The utility of these groups for mechanistic interrogation of a critical step in polyketide biosynthesis is examined through comparison to traditional probes. In all, we expect the probes described in this study to serve as valuable and versatile tools for mechanistic interrogation.

| S-EPMC4232301 | biostudies-literature

Synthesis of Unsaturated Silyl Heterocycles via an Intramolecular Silyl-Heck Reaction.

Project description:We report the synthesis of unsaturated silacycles via an intramolecular silyl-Heck reaction. Using palladium catalysis, silicon electrophiles tethered to alkenes cyclize to form 5- and 6-membered silicon heterocycles. The effects of alkene substitution and tether length on the efficiency and regioselectivity of the cyclizations are described. Finally, through the use of an intramolecular tether, the first examples of disubstituted alkenes in silyl-Heck reactions are reported.

| S-EPMC7236810 | biostudies-literature

OmicsDI is part of the ELIXIR infrastructure

OmicsDI is an Elixir interoperability service. Learn more ›

Tweets

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