Browse
Submit Data
Databases
API
Help

Dataset Information

16 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Enantioselective intramolecular C-H insertion reactions of donor-donor metal carbenoids.

ABSTRACT: The first asymmetric insertion reactions of donor-donor carbenoids, i.e., those with no pendant electron-withdrawing groups, are reported. This process enables the synthesis of densely substituted benzodihydrofurans with high levels of enantio- and diastereoselectivity. Preliminary results show similar efficiency in the preparation of indanes. This new method is used in the first enantioselective synthesis of an oligoresveratrol natural product (E-δ-viniferin).

SUBMITTER: Soldi C

PROVIDER: S-EPMC4227726 | biostudies-literature |

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Similar Datasets

Catalytic enantioselective O-H insertion reactions.

Project description:The first effective method for catalytic enantioselective insertions into O-H bonds has been developed. Specifically, a copper/bisazaferrocene catalyst couples alcohols such as 2-trimethylsilylethanol with alpha-aryl-alpha-diazo esters in high yield and good ee.

| S-EPMC2517123 | biostudies-literature

Enantioselective synthesis of isochromans and tetrahydroisoquinolines by C-H insertion of donor/donor carbenes.

Project description:Reports of C-H insertions forming six-membered rings containing heteroatoms are rare due to Stevens rearrangements occurring after nucleophilic attack on the carbene by a heteroatom. Using donor/donor carbenes and Rh2(R-PTAD)4 as a catalyst, we have synthesized a collection of isochroman substrates in good yield, with excellent diastereo- and enantioselectivity, and no rearrangement products were observed. Furthermore, we report the first synthesis of six-membered rings containing nitrogen by C-H insertion to form tetrahydroisoquinolines. In one case, a Stevens rearrangement product was isolated at elevated temperature from a carbamate-protected amine substrate and computational evidence suggests formation through a free ylide not bound to rhodium.

| S-EPMC7439777 | biostudies-literature

Enantioselective S-H Insertion Reactions of α-Carbonyl Sulfoxonium Ylides.

Project description:The first example of enantioselective S-H insertion reactions of sulfoxonium ylides is reported. Under the influence of thiourea catalysis, excellent levels of enantiocontrol (up to 95 % ee) and yields (up to 97 %) are achieved for 31 examples in S-H insertion reactions of aryl thiols and α-carbonyl sulfoxonium ylides.

| S-EPMC7606806 | biostudies-literature

Intramolecular Carbene C-H Insertion Reactions of 2-Diazo-2-sulfamoylacetamides.

Project description:The intramolecular C-H insertions of carbenes derived from 2-diazo-2-sulfamoylacetamides were studied. 2-Diazo-2-sulfamoylacetamides were first prepared from chloroacetyl chloride and secondary amines through acylation followed by sequential treatments with sodium sulfite, phosphorus oxychloride, secondary amines, and 4-nitrobenzenesulfonyl azide. The results indicate that: (1) 2-diazo-N,N-dimethyl-2-(N,N-diphenylsulfamoyl)acetamide can take the formal aromatic 1,5-C-H insertion in its N-phenylsulfonamide moiety to afford the corresponding 1,3-dihydrobenzo[c]isothiazole-3-carboxamide 2,2-dioxide derivative; (2) no aliphatic C-H insertions occur for 2-diazo-2-(N,N-dialkylsulfamoyl)acetamides; and (3) for 2-diazo-N-phenyl-2-(N-phenylsulfamoyl)acetamides, the formal aromatic 1,5-C-H insertion in the N-phenylacetamide moiety is favorable to afford the corresponding 3-sulfamoylindolin-2-one derivatives as sole or major products. The intramolecular competitive aromatic 1,5-C-H insertion reactions of 2-diazo-2-sulfamoylacetamides with aryl groups on both amide and sulfonamide groups reveal that the N-aryl substituents on acetamide are more active than those on sulfonamide. The chemoselectivity is controlled by electronic effect of the aryl group.

| S-EPMC6680402 | biostudies-literature

Enantioselective Synthesis of Indolines, Benzodihydrothiophenes, and Indanes by C-H Insertion of Donor/Donor Carbenes.

Project description:We employ a single catalyst/oxidant system to enable the asymmetric syntheses of indolines, benzodihydrothiophenes, and indanes by C-H insertion of donor/donor carbenes. This methodology enables the rapid construction of densely substituted five-membered rings that form the core of many drug targets and natural products. Furthermore, oxidation of hydrazones to the corresponding diazo compounds proceeds in situ, enabling a relatively facile one- or two-pot protocol in which isolation of potentially explosive diazo alkanes is avoided. Regioselectivity studies were performed to determine the impact of sterics and electronics in donor/donor metal carbene C-H insertions to form indolines. This methodology was applied to a variety of substrates in high yield, diastereomeric, and enantiomeric ratios and to the synthesis of a patented indane estrogen receptor agonist with anti-cancer activity.

| S-EPMC6377237 | biostudies-literature

A Chiral Thiourea as a Template for Enantioselective Intramolecular [2 + 2] Photocycloaddition Reactions.

Project description:A chiral (1R,2R)-diaminocyclohexane-derived bisthiourea was found to exhibit a significant asymmetric induction in the intramolecular [2 + 2] photocycloaddition of 2,3-dihydropyridone-5-carboxylates. Under optimized conditions, the reaction was performed with visible light employing 10 mol % of thioxanthone as triplet sensitizer. Due to the different electronic properties of its carbonyl oxygen atoms, a directed binding of the substrate to the template is possible, which in turn enables an efficient enantioface differentiation.

| S-EPMC4994062 | biostudies-literature

Enantioselective synthesis of ?-alkenyl ?-amino acids via N-H insertion reactions.

Project description:A new highly enantioselective route to ?-alkenyl ?-amino acid derivatives, which are important naturally occurring compounds with attractive bioactivity and synthetic utility, was developed using a N-H insertion reaction of vinyldiazoacetates and tert-butyl carbamate cooperatively catalyzed by achiral dirhodium(ii) carboxylates and chiral spiro phosphoric acids under mild, neutral conditions. This reaction has a broad substrate scope, a fast reaction rate (turnover frequency > 6000 h-1), a high yield (61-99%), and excellent enantioselectivity (83-98% ee). The chiral spiro phosphoric acid, which is proposed to realize the enantioselectivity of the insertion reaction by promoting the proton transfer of a ylide intermediate by acting as a chiral proton shuttle catalyst, can suppress several usual side reactions of vinyldiazoacetates and broaden the applications of these versatile carbene precursors in organic synthesis. To our knowledge, it is the first highly enantioselective carbene insertion reaction of vinyldiazoacetates with heteroatom-hydrogen bonds in which the heteroatom has lone-pair electrons.

| S-EPMC5975786 | biostudies-other

Vinyl Carbocations Generated under Basic Conditions and Their Intramolecular C-H Insertion Reactions.

Project description:Here we report the surprising discovery that high-energy vinyl carbocations can be generated under strongly basic conditions, and that they engage in intramolecular sp3 C-H insertion reactions through the catalysis of weakly coordinating anion salts. This approach relies on the unconventional combination of lithium hexamethyldisilazide base and the commercially available catalyst, triphenylmethylium tetrakis(pentafluorophenyl)borate. These reagents form a catalytically active lithium species that enables the application of vinyl cation C-H insertion reactions to heteroatom-containing substrates.

| S-EPMC6608570 | biostudies-literature

Cytochrome P450-Catalyzed Insertion of Carbenoids into N-H Bonds.

Project description:Expanding nature's catalytic repertoire to include reactions important in synthetic chemistry will open new opportunities for 'green' chemistry and biosynthesis. We demonstrate enzyme-catalyzed insertion of carbenoids into N-H bonds. This type of bond disconnection, which has no counterpart in nature, can be mediated by variants of the cytochrome P450 from Bacillus megaterium. The N-H insertion reaction takes place in water, provides the desired products in 26-83% yield, forms the single addition product exclusively, and does not require slow addition of the diazo component.

| S-EPMC3906682 | biostudies-literature

Enantioselective Si-H Insertion Reactions of Diarylcarbenes for the Synthesis of Silicon-Stereogenic Silanes.

Project description:We report the first example of enantioselective, intermolecular diarylcarbene insertion into Si-H bonds for the synthesis of silicon-stereogenic silanes. Dirhodium(II) carboxylates catalyze an Si-H insertion using carbenes derived from diazo compounds where selective formation of an enantioenriched silicon center is achieved using prochiral silanes. Fourteen prochiral silanes were evaluated with symmetrical and prochiral diazo reactants to produce a total of 25 novel silanes. Adding an ortho substituent on one phenyl ring of a prochiral diazo enhances enantioselectivity up to 95:5 er with yields up to 98%. Using in situ IR spectroscopy, the impact of the off-cycle azine formation is supported based on the structural dependence for relative rates of diazo decomposition. A catalytic cycle is proposed with Si-H insertion as the rate-determining step, supported by kinetic isotope experiments. Transformations of an enantioenriched silane derived from this method, including selective synthesis of a novel sila-indane, are demonstrated.

| S-EPMC7747653 | biostudies-literature

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