1,2-Difunctionalization of Aryne with Sulfenamide and Organohalide: Mild and Metal-Free Access to S-(o-Halo)aryl Sulfilimine.

A mild and metal-free approach has been developed for 1,2-difunctionalization of aryne using sulfenamides as a nucleophile and a halogen source (CX4) as an electrophile to synthesize S-(o-halo)aryl sulfilimines. The late-stage functionalizations of halide handles via Suzuki-Miyaura and Buchwald-Hartwig reactions exhibit the synthetic utilities of the products. The chemoselectivity, regioselectivity, rapidity, and use of economical CCl4 are the advantages of this protocol.

Visible Light Mediated Co-Catalyzed Isocyanide Insertion with Sulfonyl Azide: Synthesis of Sulfonyl Carbamimidic Azide and Sulfonyl Aminotetrazole via Carbodiimide Intermediate.

Herein, we report an operationally simple and efficient protocol to prepare sulfonyl carbamimidic azide and N-sulfonyl aminotetrazole via Co-catalyzed three component coupling of sulfonyl azide (acts as nitrene source), isocyanide, and TMS-azide at room temperature under visible light. Initially, the carbamimidic azide is formed, which cyclizes only in the presence of base to deliver N-sulfonyl aminotetrazole in very good yields. The sulfonyl aminotetrazole can also be synthesized directly without isolating the carbamimidic azide in the presence of base. The sulfonyl azide is anticipated to generate nitrene and reacts with isocyanide to produce carbodiimide. Subsequent addition of azide (TMS-N3 ) to carbodiimide results in the formation of carbamimidic azide.

Ni-Catalyzed Mild Synthesis of Sulfonylurea via Tandem Coupling of Sulfonyl Azide, Isocyanide, and Water.

An efficient, mild, and novel route is developed to synthesize sulfonylurea via the nickel-catalyzed tandem coupling of sulfonyl azide, isocyanide, and water in aqueous media. The sulfonyl azide is expected to act as a nitrene precursor, which upon reaction with isocyanide generates carbodiimide. Herein, water acts as a nucleophile and reacts with carbodiimide to deliver the product. The protocol uses an inexpensive nickel catalyst, environmentally friendly water (as the nucleophile), and room temperature and provides products in moderate to good yields.

One-pot synthesis of α-sulfoximinophosphonate via Kabachnik-Fields reaction.

Herein, we disclose a novel approach for the synthesis of hitherto unknown α-sulfoximinophosphonate via the Kabachnik-Fields reaction of aldehyde, dialkylphosphite and sulfoximine in the presence of InCl3 in THF at 70 °C. α-Sulfoximinophosphonate is synthesized in good yields and its synthetic utilities are proved by functionalizing bromine through the Pd-catalyzed Suzuki-Miyaura cross-coupling reaction and reduction of a nitro group through the Béchamp reduction.

A metal-free Petasis reaction towards the synthesis of N-(α-substituted)alkyl sulfoximines/sulfonimidamides.

Herein, we disclose a metal-free novel approach for the synthesis of N-(α-substituted)alkyl sulfoximines/sulfonimidamides via one-pot multicomponent Petasis reactions of aryl boronic acids, ortho-hydroxyarylaldehydes and sulfoximines/sulfonimidamides in moderate to very good yields. The presence of two chiral centres provides a mixture of diastereomers almost in a 1 : 1 ratio, which are separated successfully in most of the cases. The -OH functionality of Petasis products is further utilized to derive heterocycles via O-allylation, followed by intramolecular Heck cyclization, proving the synthetic utility of the products.

Catalyst-Controlled Dual Reactivity of Sulfonimidamides: Synthesis of Propargylamines and N-Propargyl Sulfonimidamides.

Sulfonimidamides (SIAs) are acting both as surrogate amines and nucleophiles depending on the reaction conditions to access propargylamines and N-propargyl SIAs, respectively. The amine part of SIAs has been cleaved in an InCl3 -catalyzed three-component A3 coupling reaction with aldehyde and acetylene to yield propargylamine. Moreover, N-propargyl SIAs were obtained via the direct-imination of propargyl alcohols in the presence of BF3 ⋅OEt2 .

CuBr/TBHP-mediated synthesis of N-acyl sulfonimidamides via the oxidative cross-coupling of sulfonimidamides and aldehydes.

N-Acyl sulfonimidamides were synthesized via a Cu-catalyzed double C-H/N-H activation protocol. The imino end of sulfonimidamides was acylated using aldehyde as the acylating agent and t-butyl hydrogen peroxide (TBHP) as the oxidant in acetonitrile (MeCN) at 82 °C. The mild reaction conditions afforded low-to-moderate yields of N-acyl sulfonimidamides with high structural diversity.

p-TSA/Base-Promoted Propargylation/Cyclization of ß-Ketothioamides for the Regioselective Synthesis of Highly Substituted (Hydro)thiophenes.

Metal-free, p-toluenesulfonic acid (p-TSA)-mediated, straightforward propargylation of ß-ketothioamides with aryl propargyl alcohol has been achieved at room temperature. In addition, the reaction also provided thiazole rings as byproducts. Furthermore, the propargylated thioamides undergo intramolecular 1,5-cyclization to afford fully substituted (hydro)thiophenes in the presence of base. Notably, the approach is pot, atom, and step economical (PASE).

Catalyst-Controlled Straightforward Synthesis of Highly Substituted Pyrroles/Furans via Propargylation/Cycloisomerization of α-Oxoketene-N,S-acetals.

A facile and efficient InCl3 catalyzed one-pot synthesis of highly substituted pyrroles has been developed via a tandem propargylation/cycloisomerization reaction of α-oxoketene-N,S-acetals with propargyl alcohols. Notably, in the presence of Bronsted acid p-TSA·H2O, the reaction afforded the hydrolyzed product propargylated-1,3-dicarbonyl compounds, which upon treatment with Cs2CO3 underwent regioselective intramolecular cyclization furnishing tetrasubstituted furan derivatives.

One-pot two-component [3 + 2] cycloaddition/annulation protocol for the synthesis of highly functionalized thiophene derivatives.

An efficient and experimentally rapid protocol for the synthesis of hitherto unreported 2,3-dicarboalkoxy-4-aroyl/heteroaroyl/alkanoyl thiophenes has been developed via 1-2 (C-S) and 3-4 (C-C) bond connections promoted by 4-dimethylaminopyridine (DMAP). Optimally, the reaction takes only 3-5 min when ß-oxodithioester and dialkyl acetylenedicarboxylate are stirred in DCM at room temperature in the presence of DMAP. This method allows a clean and general synthesis of previously inaccessible and synthetically demanding thiophenes containing the ferrocenyl group. The speed, experimental ease, and high yields of this process are improvements over existing methods to access this important substructure.

Applications of Carbon Dots (CDs) in Latent Fingerprints Imaging.

Carbon dots (CDs), a new member of the carbon-based material family, possess unique properties, such as high fluorescence, non-toxicity, eco-friendliness, stability and cost-effectiveness. These properties helped CDs to receive tremendous attention in various fields, namely, biological, opto-electronic, bio-imaging and energy-related applications. Although CDs are widely explored in bio-imaging and bio-sensing applications, their effectiveness in forensic science and technology is comparatively new. In this review, applications of CDs pertaining to latent FPs recovery since 2015 to 2020 is summarized comprehensively.

Biginelli and Hantzsch-type reactions leading to highly functionalized dihydropyrimidinone, thiocoumarin, and pyridopyrimidinone frameworks via ring annulation with ß-oxodithioesters.

An efficient and highly convergent route to dihydropyrimidinones (DHPMs) and hitherto unreported dihydropyridopyrimidinones has been developed by one-pot, three-component cyclocondensation of aromatic aldehydes, ß-oxodithioesters, and urea/6-amino-1,3-dimethyluracil in the presence of recyclable SiO2-H2SO4. On the other hand, salicylaldehyde, ß-oxodithioester, and urea reacted under similar conditions to afford the 3-aroyl/heteroaroyl-2H-chromen-2-thiones in high yields instead of Biginelli product. The attractive feature of this approach is the synthesis of three important bioactive heterocyclic frameworks from the same ß-oxodithioester under the similar reaction conditions, making this new strategy highly useful in diversity-oriented synthesis (DOS).

Regioselective synthesis of tetrahydrothiochromen-5-ones via a one-pot three-component solvent-free domino protocol.

A highly efficient one-pot three-component regioselective synthesis of 4-aryl-3-aroyl-2-methylsulfanyl-4,6,7,8-tetrahydrothiochromen-5-ones has been developed by annulation of ß-oxodithioesters with aldehydes and cyclic 1,3-diketones under solvent-free conditions promoted by P(2)O(5). No cocatalyst or activator is needed in this protocol. The merit of this process is highlighted by its high efficiency of producing three new bonds and a stereocenter in one operation.