A short enantioselective synthesis of (+)-L-733,060 via Shi epoxidation of a homoallylic carboxylate

A short and efficient enantioselective synthesis of (+)-L-733,060 in 92% ee via Shi epoxidation of a homoallylic carboxylate is described. Johnson-Claisen rearrangement was employed to obtain the required carbon backbone, whilst intramolecular reductive O-to-N-ring expansion of a δ-azidolactone was used in the construction of the piperidine moiety.     

NaIO4-mediated selective oxidation of alkylarenes and benzylic bromides/alcohols to carbonyl derivatives using water as solvent

A new transition-metal-free, sodium metaperiodate (NaIO4)-mediated direct oxidation of methylarenes and benzylic bromides to the corresponding aromatic carboxylic acids is described. Under the same reaction conditions, benzylic alcohols are selectively oxidized to afford the corresponding aldehydes in good yields without undergoing overoxidation. Unprecedentedly, oxidation of benzyl bromide, toluene, or benzyl alcohol with NaIO4 underwent nuclear bromination followed by oxidation to give 4-bromobenzoic acid in 60-79% yields.     

NaIO4/KI/NaCl: a new reagent system for iodination of activated aromatics through in situ generation of iodine monochloride

A new reagent system consisting of NaIO₄/KI/NaCl in aq AcOH has been found to be effective in iodinating a variety of activated aromatic substrates via in situ-generated iodine monochloride, to furnish iodoaromatics in excellent yields. This iodination procedure has been applied successfully for a cost-effective synthesis of 3,3′-diaminobenzidine, a key intermediate for preparing proton conducting membranes for fuel cell applications, with high yield and a purity of 99.7%.     

NaIO4/LiBr‐Mediated Direct Conversion of Benzylic Alcohols and Aromatic Aldehydes to Aromatic Esters

Aromatic aldehydes or benzylic alcohols are directly converted to the corresponding aromatic esters in high yields on treatment with methanol or ethanol mediated by sodium metaperiodate (NaIO₄)/LiBr in an acidic medium.     

A concise enantioselective synthesis of (+)-febrifugine

A short enantioselective synthesis of (+)-febrifugine, a potent antimalarial alkaloid, has been described based on the regioselective asymmetric dihydroxylation of a 1,4-dienic ester as the key step. The strategy also involves chemoselective [3,3]-sigmatropic rearrangement of 1,5-hexadiene-3-ol and intramolecular lactamization of azidolactone for the construction of piperidine core.     

Rhodium-catalyzed synthesis of 2,3 – Disubstituted N-methoxy pyrroles and furans via [3+2] cycloaddition between metal carbenoids and activated olefins

For the first time, we report the synthesis of 2-substituted N-alkoxy pyrrole 3-carboxylate and furan 3-carboxylate via Rh-catalyzed [3+2] cycloaddition between α-diazo oxime ether or α-diazo carbonyl compounds with vinyl equivalents in a one-pot process. We have demonstrated ethyl vinyl ether as well as vinyl acetate as vinyl equivalents and both were found to give excellent yields. We have also demonstrated the synthesis of N-alkoxy dihydropyrrole derivatives by carrying out the reaction at low temperature.     

Synthesis of 2-aminofurans and 2-unsubstituted furans via carbenoid-mediated [3 + 2] cycloaddition

An efficient dual synthetic manifold for 2-aminofurans and 2-unsubstituted furans has been developed. The carbenoid-mediated [3 + 2] cycloaddition of copper carbenoids with enamines provides 2-amino-2,3-dihydrofurans which serve as common intermediates for both 2-aminofurans and 2-unsubstituted furans.     

Unprecedented cyclization of α-diazo hydrazones upon N-H functionalization: A Et3N base promoted one-step synthetic approach for the synthesis of N-amino-1,2,3-triazole derivatives from α-diazo hydrazone

In this communication, for the first time, we are reporting α-diazo hydrazone synthesis from hydrazones derived from β-keto esters and 2,4-dinitro phenyl hydrazine via diazo transfer reaction. We also report an unexpected cyclization of the α-diazo hydrazones upon N-H functionalization to give highly functionalized N-amino-1,2,3-triazole derivatives under metal-free condition. This one-step synthetic protocol can serve as a general tool to access nitrogen rich 5- and 6-membered heterocycles in excellent yields.     

Microwave-Assisted Synthesis and Characterization of Triton X 100 Capped Silver Nanospheres

In this article, we report the synthesis of silver nanospheres (Ag NS) by a simple microwave irradiation method using Triton X 100 (TX 100) as a capping agent. TX 100 was also observed to act as a reducing agent in the presence of microwave radiation. From the ultraviolet-visible spectrum, the formation of Ag NS was confirmed by observing surface plasmon resonance band at 414 nm. The emission band of Ag NS was observed at 482 nm from the photoluminescence (PL) spectrum. High-resolution transmission electron microscopy (HR TEM) was used to investigate the morphology of the synthesized sample. It shows that the synthesized sample has sphere-like morphology with an average diameter of 5 nm. Further, the elemental composition of the Ag NS was determined by energy dispersive x-ray analysis (EDX). Selected area electron diffraction (SAED) was used to find the crystalline nature of the Ag NS. The interaction between Ag NS and TX 100 was established by Raman spectroscopy. The electrochemical behaviour of the synthesized Ag NS was analyzed by cyclic voltammetry (CV).