Browse
Submit Data
Databases
API
Help

Dataset Information

28 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Temperature dependence of turnover in a Sc(OTf)3-catalyzed intramolecular Schmidt reaction.

ABSTRACT: The intramolecular Schmidt reaction of ketones and tethered azides is an efficient method for the generation of amides and lactams. This reaction is catalyzed by Lewis acids, which tightly bind the strongly basic amide product and result in product inhibition. We report herein conditions to achieve a catalytic Schmidt reaction using substoichiometric amounts of the heat-stable Lewis acid Sc(OTf)3. This species was shown to effectively release products of the Schmidt reaction in a temperature-dependent fashion. Thus, heat was able to promote catalyst turnover. A brief substrate scope was conducted using these conditions.

SUBMITTER: Fehl C

PROVIDER: S-EPMC4465195 | biostudies-literature | 2015 Jun

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Publications

Temperature dependence of turnover in a Sc(OTf)3-catalyzed intramolecular Schmidt reaction.

Fehl Charlie C Hirt Erin E EE Li Sze-Wan SW Aubé Jeffrey J

Tetrahedron letters 20150601 23

The intramolecular Schmidt reaction of ketones and tethered azides is an efficient method for the generation of amides and lactams. This reaction is catalyzed by Lewis acids, which tightly bind the strongly basic amide product and result in product inhibition. We report herein conditions to achieve a catalytic Schmidt reaction using substoichiometric amounts of the heat-stable Lewis acid Sc(OTf)3. This species was shown to effectively release products of the Schmidt reaction in a temp ...[more]

PMID: 26085693

Similar Datasets

Homogeneous Sc(OTf)3-Catalyzed Direct Allylation Reactions of General Alcohols with Allylsilanes.

Project description:Homogeneous Sc(OTf)3 used in nitromethane showed excellent catalytic activity for the direct allylation reactions of general alcohols including benzylic, propargylic, allylic, and some aliphatic alcohols with allyltrimethylsilane under mild and neutral reaction conditions. Metal-free β-silyl-substituted carbocations are intermediates generated by the highly oxophilic Sc(OTf)3-assisted rapid removal of a hydroxyl group in alcohols, which is supported by the result that allylation of (R)-1-(naphthalen-2-yl)ethan-1-ol with allytrimethylsilanes using the Sc(OTf)3 catalyst combined with (R)- or (S)-[1,1'-binaphthalene]-2,2'-diol ligands gave only racemic 2-(pent-4-en-2-yl)naphthalene in quantitative yield. The present study resolves the argument about the uncertain catalytic activity of Sc(OTf)3.

| S-EPMC6643996 | biostudies-literature

Overcoming product inhibition in catalysis of the intramolecular Schmidt reaction.

Project description:A method for carrying out the intramolecular Schmidt reaction of alkyl azides and ketones using a substoichiometric amount of catalyst is reported. Following extensive screening, the use of the strong hydrogen-bond-donating solvent hexafluoro-2-propanol was found to be consistent with low catalyst loadings, which ranged from 2.5 mol % for favorable substrates to 25 mol % for more difficult cases. Reaction optimization, broad substrate scope, and preliminary mechanistic studies of this improved version of the reaction are described.

| S-EPMC3921892 | biostudies-literature

Synthesis of crispine A analogues via an intramolecular Schmidt reaction.

Project description:An intramolecular Schmidt reaction strategy for the synthesis of various derivatives of crispine A using azido-ketone as a key intermediate is described.

| S-EPMC2213660 | biostudies-literature

Azetidine synthesis by La(OTf)3-catalyzed intramolecular regioselective aminolysis of cis-3,4-epoxy amines.

Project description:Azetidine is a prevalent structural motif found in various biologically active compounds. In this research paper, we report La(OTf)3-catalyzed intramolecular regioselective aminolysis of cis-3,4-epoxy amines to afford azetidines. This reaction proceeded in high yields even in the presence of acid-sensitive and Lewis basic functional groups.

| S-EPMC10546187 | biostudies-literature

Bi(OTf)3-catalysed intramolecular cyclisation of unsaturated acetals.

Project description:A series of highly functionalized carbocycles was efficiently prepared via the selective cyclisation of unsaturated acetals and ketals in the presence of only 1 mol% of Bi(iii) or Fe(iii) triflates as the catalysts at room temperature, with yields ranging from 60 to 90%. With Bi(OTf)3 catalysis, α,β-unsaturated ether carbocycles are formed selectively, whereas with the Fe(OTf)3 system, a cycloisomerisation to carbocyclic diethers is mainly obtained. This acetal/olefin cyclisation could be run at a multi-gram scale and compound 2c could be obtained on a 300 gram-scale with a yield of 69% after precipitation in hexane.

| S-EPMC9034051 | biostudies-literature

Stereocontrol in a combined allylic azide rearrangement and intramolecular Schmidt reaction.

Project description:Pre-equilibration of an interconverting set of isomeric allylic azides is coupled with an intramolecular Schmidt reaction to afford substituted lactams stereoselectively. The effect of substitution and a preliminary mechanistic study are reported. The synthetic potential of this method is demonstrated in the context of an enantioselective synthesis of an advanced intermediate leading toward pinnaic acid.

| S-EPMC3340293 | biostudies-literature

Functionalized Cyclopentanes via Sc(III)-Catalyzed Intramolecular Enolate Alkylation.

Project description:We report herein the intramolecular ?-tert-alkylation of unsaturated ?-ketoesters which gives rise to highly functionalized cyclopentanes. This strategy is characterized by its operational simplicity, mild reaction conditions and the use of scandium(III) triflate as a Lewis acid catalyst. Of interest, cyclopentanes bearing heterocycles, sites for post reaction functionalization and spirocyclic architectures are accessible with this strategy.

| S-EPMC6152925 | biostudies-literature

Synthesis, structural analysis, and reactivity of bridged orthoamides by intramolecular Schmidt reaction.

Project description:Intramolecular Schmidt reactions can be reliably steered toward bridged heterocycles containing orthoamides in high yields. The ketal tether enhances the control of regioselectivity in the migration of the bond distal to the reactive azide nucleophile, thus providing the first examples of the intramolecular Schmidt reaction proceeding with a complete regioselectivity en route to bridged products. The method is broad in scope and allows for systematic study of compounds that are analogous to elusive tetrahedral intermediates of amide addition reactions. Some initial reactivity and structural profiling of these compounds are also reported.

| S-EPMC2828530 | biostudies-literature

Sc(OTf)3-Mediated [4 + 2] Annulations of N-Carbonyl Aryldiazenes with Cyclopentadiene to Construct Cinnoline Derivatives: Azo-Povarov Reaction.

Project description:We disclose the first accomplishment of the azo-Povarov reaction involving Sc(OTf)3-catalyzed [4 + 2] annulations of N-carbonyl aryldiazenes with cyclopentadiene in chloroform, in which N-carbonyl aryldiazenes act as 4π-electron donors. Hence, this protocol offers a rapid access to an array of cinnoline derivatives in moderate to good yields for substrates over a wide scope. The synthetic potential of the protocol was achieved by the gram-scale reaction and further derivatization of the obtained polycyclic product.

| S-EPMC9447289 | biostudies-literature

Hg(OTf)2 Catalyzed Intramolecular 1,4-Addition of Donor-Acceptor Cyclopropenes to Arenes.

Project description:A Hg(OTf)2 catalyzed intramolecular arene 1,4-addition reaction of N-benzyl donor-acceptor cyclopropenecarboxamides was developed to synthesize a series of [3.2.2]nonatriene derivatives. This novel reaction is also observed with silver(I) catalysts known to form metal carbene intermediates in competition with the Buchner reaction.

| S-EPMC5572213 | biostudies-literature