Transition metal-free iminoiodane-mediated amination of activated C-H bonds

Novel transition metal-free-mediated amination of C–H bonds with the use of arylsulfonyliminophenyliodinane (PhI=NSO2Ar) have been developed. The use of iodine(III) compound has shown to be compatible under Brønsted acid and base conditions for the synthesis of unnatural amino ester derivatives and aziridines from 1,3-dicarbonyl compounds, respectively. The amination of cyclic ethers with iminoiodanes was explored subsequently. These cyclic ethers could undergo ring opening and further functionalization with nucleophiles was realized to give the 2-substituted cyclic ether and amino alcohol products under their respective reaction conditions.DOCTOR OF PHILOSOPHY (SPMS

Gold( i )-catalyzed 6-endo-dig azide–yne cyclization: efficient access to 2H-1,3-oxazines

International audienceDenitrogenative 6-endo-dig azide-yne cyclization of α-propargyloxy-β-haloalkylazides was enabled by gold catalysis, thus providing 2H-1,3-oxazines. This rare cyclization mode in gold-catalyzed reactions of azide-yne substrates was demonstrated to be facilitated and controlled by electronic and resonance effects of the alkyne substituents. Molecular transformations of the as-prepared 2H-1,3-oxazines were also investigated

Hydrodehalogenation of haloarenes by a sodium hydride-iodide composite

A simple protocol for hydrodebromination and -deiodination of halo(hetero)arenes was enabled by sodium hydride (NaH) in the presence of lithium iodide (LiI). Mechanistic studies showed that an unusual concerted nucleophilic aromatic substitution operates in the present process.Nanyang Technological UniversityAccepted versionThis work was financially supported by Nanyang Technological University (NTU)

Alkyl Ethers as Traceless Hydride Donors in Brønsted Acid Catalyzed Intramolecular Hydrogen Atom Transfer

International audienceA new protocol for the deoxygenation of alcohols and the hydrogenation of alkenes under Brønsted acid catalysis has been developed. The method is based on the use of either a benzyl or isopropyl ether as a traceless hydrogen-atom donor, and involves an intramolecular hydride transfer as a key step, which is achieved in a regio- and stereoselective manner

Copper(II) triflate catalyzed amination and aziridination of 2-alkyl substituted 1,3-dicarbonyl compounds

A method to prepare α-acyl-β-amino acid and 2,2-diacyl aziridine derivatives efficiently from Cu(OTf)2 + 1,10-phenanthroline (1,10-phen)-catalyzed amination and aziridination of 2-alkyl substituted 1,3-dicarbonyl compounds with PhI═NTs is described. By taking advantage of the orthogonal modes of reactivity of the substrate through slight modification of the reaction conditions, a divergence in product selectivity was observed. In the presence of 1.2 equiv of the iminoiodane, amination of the allylic C—H bond of the enolic form of the substrate, formed in situ through coordination to the Lewis acidic metal catalyst, was found to selectively occur and give the β-aminated adduct. On the other hand, increasing the amount of the nitrogen source from 1.2 to 2–3 equiv was discovered to result in preferential formal aziridination of the C—C bond of the 2-alkyl substituent of the starting material and formation of the aziridine product

Dearylation of arylphosphine oxides using a sodium hydride–iodide composite

A new protocol for the dearylation of arylphosphine oxides was developed using sodium hydride (NaH) in the presence of lithium iodide (LiI). The transient sodium phosphinite could be functionalized with a range of electrophiles in a one-pot fashion.MOE (Min. of Education, S’pore)Accepted versio

Brønsted Base-Mediated Aziridination of 2-Alkyl-Substituted-1,3-Dicarbonyl Compounds and 2-Acyl-Substituted-1,4-Dicarbonyl Compounds by Iminoiodanes

The synthesis of α,α-diacylaziridines and α,α,β-triacylaziridines from reaction of 2-alkyl-substituted-1,3-dicarbonyl compounds and 2-acyl-substituted-1,4-dicarbonyl compounds with arylsulfonyliminoiodinanes (ArSO2N=IPh) under Brønsted base-mediated atmospheric conditions is described. The reaction mechanism is thought to involve the formal oxidation of the substrate followed by aziridination of the ensuing α,β-unsaturated intermediate by the hypervalent iodine(III) reagent.Accepted versio

Copper(II) Triflate Catalyzed Amination and Aziridination of 2-Alkyl Substituted 1,3-Dicarbonyl Compounds

A method to prepare α-acyl-β-amino acid and 2,2-diacyl aziridine derivatives efficiently from Cu­(OTf)₂ + 1,10-phenanthroline (1,10-phen)-catalyzed amination and aziridination of 2-alkyl substituted 1,3-dicarbonyl compounds with PhINTs is described. By taking advantage of the orthogonal modes of reactivity of the substrate through slight modification of the reaction conditions, a divergence in product selectivity was observed. In the presence of 1.2 equiv of the iminoiodane, amination of the allylic CH bond of the enolic form of the substrate, formed in situ through coordination to the Lewis acidic metal catalyst, was found to selectively occur and give the β-aminated adduct. On the other hand, increasing the amount of the nitrogen source from 1.2 to 2–3 equiv was discovered to result in preferential formal aziridination of the CC bond of the 2-alkyl substituent of the starting material and formation of the aziridine product

Copper(II) Triflate Catalyzed Amination and Aziridination of 2-Alkyl Substituted 1,3-Dicarbonyl Compounds

A method to prepare α-acyl-β-amino acid and 2,2-diacyl aziridine derivatives efficiently from Cu­(OTf)₂ + 1,10-phenanthroline (1,10-phen)-catalyzed amination and aziridination of 2-alkyl substituted 1,3-dicarbonyl compounds with PhINTs is described. By taking advantage of the orthogonal modes of reactivity of the substrate through slight modification of the reaction conditions, a divergence in product selectivity was observed. In the presence of 1.2 equiv of the iminoiodane, amination of the allylic CH bond of the enolic form of the substrate, formed in situ through coordination to the Lewis acidic metal catalyst, was found to selectively occur and give the β-aminated adduct. On the other hand, increasing the amount of the nitrogen source from 1.2 to 2–3 equiv was discovered to result in preferential formal aziridination of the CC bond of the 2-alkyl substituent of the starting material and formation of the aziridine product