Browse
Submit Data
Databases
API
Help

Dataset Information

0 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Catalytic redox-initiated glycolate aldol additions of silyl glyoxylates.

ABSTRACT: 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.

SUBMITTER: Greszler SN

PROVIDER: S-EPMC2651742 | biostudies-literature | 2009 Feb

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Publications

Catalytic redox-initiated glycolate aldol additions of silyl glyoxylates.

Greszler Stephen N SN Johnson Jeffrey S JS

Organic letters 20090201 4

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. ...[more]

PMID: 19161319

Similar Datasets

Three-component glycolate Michael reactions of enolates, silyl glyoxylates, and ?,?-enones.

Project description:Silyl glyoxylates react with enolates and enones to afford either glycolate aldol or Michael adducts. Product identity is controlled by the countercation associated with the enolate. Reformatsky nucleophiles in the presence of additional Zn(OTf)(2) result in aldol coupling (A), while lithium enolates provide the Michael coupling (B). Deprotonation of the aldol product A with LDA induces equilibration to form the minor diastereomer of Michael product B. This observation suggests that formation of the major diastereomer of Michael product B does not occur via an aldol/retro-aldol/Michael sequence.

| S-EPMC3321131 | biostudies-literature

Catalytic asymmetric addition of thiols to silyl glyoxylates for synthesis of multi-hetero-atom substituted carbon stereocenters.

Project description:A chiral Lewis acid-catalyzed enantioselective addition of thiols to silyl glyoxylates was developed. The reaction proceeds well with a broad range of thiols and acylsilanes, affording the target tertiary chiral α-silyl-α-sulfydryl alcohols with multi-hetero-atom carbon stereocenters in excellent yields (up to 99%) and enantioselectivities (up to 98% ee). A series of control experiments were conducted to elucidate the reaction mechanism.

| S-EPMC8171345 | biostudies-literature

Additive and Emergent Catalytic Properties of Dimeric Unnatural Amino Acid Derivatives: Aldol and Conjugate Additions.

Project description:Different densely substituted L- and D-proline esters were prepared by asymmetric (3+2) cycloaddition reactions catalyzed by conveniently selected EhuPhos chiral ligands. The γ-nitro-2-alkoxycarbonyl pyrrolidines thus obtained in either their endo or exo forms were functionalized and coupled to yield the corresponding γ-dipeptides. The catalytic properties of these latter dimers were examined using aldol and conjugate additions as case studies. When aldol reactions were analyzed, an additive behavior in terms of stereocontrol was observed on going from the monomers to the dimers. In contrast, in the case of the conjugate additions between ketones and nitroalkenes, the monomers did not catalyze this reaction, whereas the different γ-dipeptides promoted the formation of the corresponding Michael adducts. Therefore, in this latter case emergent catalytic properties were observed for these novel γ-dipeptides based on unnatural proline derivatives. Under certain conditions stoichiometric amounts of ketone, acid and nitroalkene), formation of N-acyloxy-2-oxooctahydro-1H-indoles was observed.

| S-EPMC9293019 | biostudies-literature

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 β-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).

| S-EPMC3115596 | biostudies-literature

Construction of cyclopentanol derivatives via three-component coupling of silyl glyoxylates, acetylides, and nitroalkenes.

Project description:The three-component coupling of Mg acetylides, silyl glyoxylates, and nitroalkenes results in a highly diastereoselective Kuwajima-Reich/vinylogous Michael cascade that provides tetrasubstituted silyloxyallene products. The regio- and diastereoselectivity were studied using DFT calculations. These silyloxyallenes were converted to cyclopentenols and cyclopentitols via a unique Lewis acid assisted Henry cyclization. The alkene functionality present in the cyclopentanol products can be elaborated using diastereoselective ketohydroxylation reactions.

| S-EPMC3265386 | biostudies-literature

Diastereoselective synthesis of pentasubstituted gamma-butyrolactones from silyl glyoxylates and ketones through a double Reformatsky reaction.

Project description:Three contiguous stereocenters can be established with remarkable diastereoselectivity in a double Reformatsky sequence. Densely functionalized gamma-butyrolactones were assembled rapidly by this approach, in which a ketone is used as the terminal electrophile (see scheme). Secondary transformations of the lactone products enhance their synthetic utility. R(1) = Me, H; R(2) = alkyl, aryl, CF(3); Bn = benzyl, TBS = tert-butyldimethylsilyl.

| S-EPMC2801152 | biostudies-literature

Silyl Anion Initiated Hydroboration of Aldehydes and Ketones.

Project description:Hydroboration is an emerging method for mild and selective reduction of carbonyl compounds. Typically, transition-metal or reactive main-group hydride catalysts are used in conjunction with a mild reductant such as pinacolborane. The reactivity of the main-group catalysts is a consequence of the nucleophilicity of their hydride ligands. Silicon hydrides are significantly less reactive and are therefore not efficient hydroboration catalysts. Here, a readily prepared silyl anion is reported to be an effective initiator for the reduction of aldehydes and ketones requiring mild conditions, low catalyst loadings and with a good substrate scope. The silyl anion it is shown to activate HBpin to generate a reactive borohydride in situ which reacts with aldehydes and ketones to afford the hydroboration product.

| S-EPMC7496802 | biostudies-literature

Lewis base catalyzed enantioselective additions of an N-silyl vinylketene imine.

Project description: Not available

| S-EPMC3529587 | biostudies-literature

Stereodivergent approach to the avermectins based on "super silyl" directed aldol reactions.

Project description:A stereodivergent approach to the spiroketal fragment of the avermectins is described. The strategy utilizes a sequence of three aldol reactions directed by the tris(trimethylsilyl)silyl "super silyl" group. Central to this strategy is that each aldol reaction can be controlled to allow access to either diastereomer in high stereoselectivity, thereby affording 16 stereoisomers along the same linear skeleton. The aldol products can be transformed into spiroketals, including an advanced intermediate in the total synthesis of avermectin A1a.

| S-EPMC4120983 | biostudies-literature

Fluoride Ion-Initiated Decarboxylation of Silyl Alkynoates to Alkynylsilanes.

Project description:This communication describes the development of a metal-free catalytic decarboxylation of silyl alkynoates to alkynylsilanes. Treatment of a silyl alkynoate with a catalytic amount of tetrabutylammonium difluorotriphenylsilicate (TBAT) in N,N-dimethylformamide at 150 °C resulted in decarboxylation to give the corresponding alkynylsilane in good to excellent yield (75 → 95%). The TBAT system was applicable to the decarboxylation of sterically demanding silyl alkynoates such as tert-butyldiphenylsilyl 3-phenylpropiolate. Mechanistic studies revealed that the tetrabutylammonium alkynoate derived from TBAT and the silyl alkynoate act as a catalyst for the decarboxylation.

| S-EPMC8154224 | 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