Browse
Submit Data
Databases
API
Help
Login

Dataset Information

0 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Synthesis of gamma,delta-unsaturated glycolic acids via sequenced brook and Ireland--claisen rearrangements.

ABSTRACT: Organozinc, -magnesium, and -lithium nucleophiles initiate a Brook/Ireland-Claisen rearrangement sequence of allylic silyl glyoxylates resulting in the formation of gamma,delta-unsaturated alpha-silyloxy acids.

SUBMITTER: Schmitt DC

PROVIDER: S-EPMC2830285 | BioStudies | 2010-01-01

REPOSITORIES: biostudies

ACCESS DATA

Json Xml

Similar Datasets

Formal synthesis of leustroducsin B via Reformatsky/Claisen condensation of silyl glyoxylates.

Project description:A formal synthesis of leustroducsin B has been completed. The synthesis relies upon a recently developed Reformatsky/Claisen condensation of silyl glyoxylates and enantioenriched ?-lactones that establishes two of the molecule's three core stereocenters and permits further elaboration to an intermediate in Imanishi's synthesis via reliable chemistry (Prasad reduction, asymmetric pentenylation, Mitsunobu inversion).

2011-01-01 | S-EPMC3115596 | BioStudies

Remote stereoinduction in the acylation of fully substituted enolates: tandem Reformatsky/quaternary Claisen condensations of silyl glyoxylates and ?-lactones.

Project description:Reformatsky reagents react sequentially with silyl glyoxylates and ?-lactones to give highly functionalized Claisen condensation products. A heretofore undocumented instance of stereochemical 1,4-induction results in efficient transmission of ?-lactone stereochemistry to the emerging fully substituted stereocenter. Second-stage transformations reveal that the five heteroatom-containing functionalities embedded within the products are entirely chemo-differentiated, a circumstance that permits rapid assembly of the leustroducsin B core substructure.

2010-01-01 | S-EPMC3056164 | BioStudies

Catalytic nucleophilic glyoxylation of aldehydes.

Project description:Beta-silyloxy-alpha-keto esters are prepared through a cyanide-catalyzed benzoin-type reaction with silyl glyoxylates and aldehydes. The products undergo a dynamic kinetic resolution to provide enantioenriched orthogonally protected alcohols and can be converted to the corresponding beta-silyloxy-alpha-amino esters.

2010-01-01 | S-EPMC2890213 | BioStudies

Why do thioureas and squaramides slow down the Ireland-Claisen rearrangement?

Project description:A range of chiral hydrogen-bond-donating organocatalysts was tested in the Ireland-Claisen rearrangement of silyl ketene acetals. None of these organocatalysts was able to impart any enantioselectivity on the rearrangements. Furthermore, these organocatalysts slowed down the Ireland-Claisen rearrangement in comparison to an uncatalyzed reaction. The catalyst-free reaction proceeded well in green solvents or without any solvent. DFT calculations showed that the activation barriers are higher for reactions involving hydrogen-donating organocatalysts and kinetic experiments suggest that the catalysts bind stronger to the starting silyl ketene acetals than to transition structures thus leading to inefficient rearrangement reactions.

2019-01-01 | S-EPMC6941421 | BioStudies

Stereoselective synthesis of quaternary carbons via the dianionic Ireland-Claisen rearrangement.

Project description:A dianionic Ireland-Claisen rearrangement of chiral, nonracemic ?-methyl-?-hydroxy allylic esters has been developed that proceeds with high diastereoselectivity and provides products containing three contiguous stereogenic carbons, including a quaternary center. The potential utility of the rearrangement for complex molecule synthesis is also demonstrated.

1000-01-01 | S-EPMC4018138 | BioStudies

Attempts to improve the overall stereoselectivity of the Ireland-Claisen rearrangement.

Project description:With focus on the steric effects present in the transition states for the [3,3]-sigmatropic rearrangement, the substrate 5 has been designed to improve the overall stereoselectivity of the Ireland-Claisen rearrangement. Experimentally, it has been found that (1) only Z-6 rearranges to 7 at 80 degrees C and (2) E-6 isomerizes to Z-6 at 80 degrees C, thereby allowing the transformation of 5 into 7 in an almost quantitative yield. To illustrate the usefulness of this approach, two additional examples are given.

2009-01-01 | S-EPMC2659616 | BioStudies

Catalytic redox-initiated glycolate aldol additions of silyl glyoxylates.

Project description:Lanthanide triisopropoxides catalyze a rapid, tandem MPV reduction/Brook rearrangement/aldol sequence between silyl glyoxylates and aldehydes that achieves catalytic turnover through alkoxide transfer from a strain-release Lewis acidic silacycle.

2009-01-01 | S-EPMC2651742 | BioStudies

Conjugate addition/Ireland-Claisen rearrangements of allyl fumarates: simple access to terminally differentiated succinates.

Project description:The conjugate addition of dialkylzinc reagents to allyl fumarates with subsequent Ireland-Claisen rearrangement has been accomplished yielding substituted unsymmetrical succinic acid derivatives. This one-pot reaction creates two new carbon-carbon bonds at contiguous stereogenic centers. The reaction proceeds for several alkylzinc reagents and substituted allyl fumarates. The products contain distinguishable functional handles for further manipulation.

2008-01-01 | S-EPMC2822989 | BioStudies

Computational study of factors controlling the boat and chair transition states of Ireland-Claisen rearrangements.

Project description:The origins of the boat transition state preference in the Ireland-Claisen rearrangements studied experimentally by Kishi and co-workers have been explored computationally with Density Functional Theory. Steric interactions in the chair transition states were identified as the principal reason for the boat transition state preference.

2010-01-01 | S-EPMC2837782 | BioStudies

Unified synthesis of caged Garcinia natural products based on a site-selective Claisen/Diels-Alder/Claisen rearrangement.

Project description:A unified synthetic strategy toward caged Garcinia natural products has been designed and implemented. Central to the strategy is a tandem Claisen/Diels-Alder/Claisen rearrangement of a suitably substituted xanthone precursor to form forbesione (1a). Serving as a template, forbesione is then used to deliver representative members of this family, including desoxygaudichaudione A (4), desoxymorellin (5), and gambogin (10). Studies on the timing of this reaction cascade suggest that the C-ring Claisen/Diels-Alder rearrangement proceeds initially and is followed by the A-ring Claisen reaction. The electronic and steric effects that govern the outcome of this cascade are presented.

1000-01-01 | S-EPMC514429 | BioStudies

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