Márcio S. Silva

Synthesis of β‐Phenylchalcogeno‐α,β‐unsaturated Ketones via Hydrochalcogenation of Acetylenes using Microwave and Solvent‐Free Conditions

Abstract A simple, clean, and efficient solvent‐free protocol was developed for hydrochalcogenation of 3‐organyl‐3‐butyn‐2‐ones with phenylchalcogenolate (Se, Te, S) anions generated in situ from the respective diphenyl dichalcogenide using alumina‐supported sodium borohydride (Se, Te) or commercially available (S). This efficient and improved method is general and furnishes the (Z)‐β‐phenylchalcogeno‐α,β‐unsaturated ketones in good yield with higher selectivity compared with those that use organic solvent and an inert atmosphere. The use of microwave (MW) irradiation facilitates the procedure and accelerates the reaction.

Synthesis of enantiomerically pure bis(2,2-dimethyl-1,3-dioxolanylmethyl)chalcogenides and dichalcogenides

Herein we describe the reaction between the nucleophilic species of chalcogenium (sulfur, selenium and tellurium) and (R)- and (S)-solketal tosylates to prepare enantiomerically pure bis-1,3-dioxolanylmethyl chalcogenides and dichalcogenides in short reaction times and good yields. Furthermore, the new diselenide 4a was evaluated in the Michael reaction with acrylonitrile, giving (R)-3-[(2,3-dihydroxypropyl)selanyl]propanenitrile 6b after two steps.

Atom-Economic Synthesis of Functionalized Octahydroacridines from Citronellal or 3-(Phenylthio)-citronellal

Abstract Here we present a simple, solvent-free, one-pot, hetero-Diels–Alder reaction of (R)-citronellal or 3-(phenylthio)-citronellal with arylamines using solid-supported catalyst (SiO2/ZnCl2). This general, efficient, and improved method is selective, affording preferentially new trans-fused 3-(phenylthio)-octahydroacridines (S-OHAs) in good yields. The use of microwave irradiation facilitates the procedure and accelerates the reaction.

Chiral discrimination of β-telluride carboxylic acids by NMR spectroscopy

In this work, the nuclei (1H and 125Te) for NMR spectroscopy and enantiopure compounds as chiral solvent agents (CSAs) and chiral derivatisation agents (CDAs) were evaluated under different conditions. The structure of β-telluride carboxylic acids was also modified to observe the effect on anisochrony.

Synthesis of β-Aryl-β-sulfanyl Ketones by a Sequential One-Pot Reaction Using KF/Al2O3 in Glycerol

Abstract The title compounds were synthesized by a sequential one-pot reaction of aryl aldehydes, aryl-methyl ketones, and thiols promoted by KF/Al2O3. This methodology affords a large number of β-aryl-β-sulfanyl ketone derivatives from aliphatic and aromatic thiols in good yields and is also applicable for solid substrates. [Supplementary materials are available for this article. Go to the publishers online edition of Synthetic Communications® for the following free supplemental resource(s): Full experimental and spectral details.] GRAPHICAL ABSTRACT

Ultrasound-promoted synthesis of 2-organoselanyl-naphthalenes using Oxone® in aqueous medium as an oxidizing agent

A green methodology to synthesize 2-organoselanyl-naphthalenes based on the reaction of alkynols with diaryl diselenides is described. The electrophilic species of selenium were generated in situ, by the oxidative cleavage of the Se–Se bond of diaryl diselenides by Oxone® using water as the solvent. The reactions proceeded efficiently under ultrasonic irradiation as an alternative energy source, using a range of alkynols and diorganyl diselenides as starting materials. Through this methodology, the corresponding 2-organoselanyl-naphthalenes were obtained in moderate to good yields (56–94%) and in short reaction times (0.25–2.3 h).

Simplification of Lipase Design in the Enzymatic Kinetic Resolution of Amines by Saturation Transfer Difference NMR

In this work, we demonstrate a nuclear magnetic resonance (NMR) method for racemic amide and lipase interaction as a first-pass design method in the enzymatic kinetic resolution of amines. As a novel adaptation of commonly used protein-ligand screening NMR methodologies, this approach relies upon a lipase-amide interaction wherein the time-consuming is reduced drastically and new insights are produced during the development of biocatalysis reactions.