Enantioselective α-Trifluoromethylthiolation of Carbonyl Compounds with AgSCF3 and Trichloroisocyanuric Acid

We successfully developed an enantioselective trifluoromethylthiolation of structurally diverse carbonyl compounds. Trichloroisocyanuric acid and AgSCF3 were employed to generate active electrophilic trifluoromethylthio species in situ for asymmetric C-SCF3 bond formation. A broad variety of chiral SCF3-carbon nucleophiles (pyrazolones, β-keto esters, and β-keto amides) were obtained in excellent yields with high enantioselectivities (up to 92% ee) by Cinchona alkaloid derived squaramide catalysts. The reaction exhibits high efficiency, good enantioselectivity, and high functional group tolerance, which provided a novel and efficient way for asymmetric synthesis of trifluoromethylthiolated carbonyl compounds.

N-Trifluoromethylselenophthalimide, an Electrophilic Trifluoromethylselenolation Reagent and Its Application for the Synthesis of 4-Trifluoromethylselenolated Isoxazoles

A new electrophilic trifluoromethylselenolation reagent, N-trifluoromethylselenophthalimide (Phth-SeCF3), was developed. A strategy for the synthesis of 4-trifluoromethylselenolated isoxazoles through electrophilic trifluoromethylselenolation cyclization has been established by using Phth-SeCF3 as an electrophilic reagent. Moreover, this protocol has the features of broad substrate scope, good functional group tolerance, and high yields.

N-Sulfenylsuccinimide/phthalimide: an alternative sulfenylating reagent in organic transformations

In the field of organosulfur chemistry, sulfenylating agents are an important key in C-S bond formation strategies. Among various organosulfur precursors, N-sulfenylsuccinimide/phthalimide derivatives have shown highly electrophilic reactivity for the asymmetric synthesis of many organic compounds. Hence, in this review article, we focus on the application of these alternative sulfenylating reagents in organic transformations.

Organoselenium Compounds: Chemistry and Applications in Organic Synthesis

Selenium, originally described as a toxin, turns out to be a crucial trace element for life that appears as selenocysteine and its dimer, selenocystine. From the point of view of drug developments, selenium-containing drugs are isosteres of sulfur and oxygen with the advantage that the presence of the selenium atom confers antioxidant properties and high lipophilicity, which would increase cell membrane permeation leading to better oral bioavailability. In this article, we have focused on the relevant features of the selenium atom, above all, the corresponding synthetic approaches to access a variety of organoselenium molecules along with the proposed reaction mechanisms. The preparation and biological properties of selenosugars, including selenoglycosides, selenonucleosides, selenopeptides, and other selenium-containing compounds will be treated. We have attempted to condense the most important aspects and interesting examples of the chemistry of selenium into a single article.

Squaramide-catalyzed asymmetric regioselective allylic alkylation of 4-aminopyrazolones with Morita-Baylis-Hillman carbonates

An efficient squaramide-catalyzed asymmetric allylic alkylation of 4-aminopyrazolones with various MBH carbonates via different pathways has been described. This method provides access to a series of pyrazolone derivatives bearing a nitrogen-containing quaternary stereocenter in high yields with excellent enantioselectivities and regioselectivities under mild conditions. In addition, we utilized the target products to construct a range of bi-heterocyclic skeletons through [3 + 2] cycloadditions. These novel hybrid heterocycles would be promising candidates for drug-discovery programs and chemical biology.

One-pot synthesis of 11-sulfenyl dibenzodiazepines via tandem sulfenylation/cyclization of o-isocyanodiaryl amines and diaryl disulfides

A one-pot sulfenylation/cyclization of o-isocyanodiaryl amines has been described for the preparation of 11-sulfenyl dibenzodiazepines. This AgI-catalyzed reaction covers an unexplored tandem process to give seven-membered N-heterocycles. This transformation shows a broad range of substrate scope, simple operation, and moderate to good yields under aerobic conditions. Diphenyl diselenide can also be produced in an acceptable yield.

Recent advances in the applications of pyrazolone derivatives in enantioselective synthesis

Pyrazolones and pyrazoles, featuring nitrogen-nitrogen bonds, are two of the most important classes of heterocycles, owing to their widespread occurrence in medicinal chemistry and functional materials. The last decade has witnessed a rapid increase in the construction of chiral pyrazolone and pyrazole derivatives, with the application of pyrazolone derivatives as powerful synthons. Since our last review in 2018, a large number of new achievements has emerged in this area, requiring a timely update. Thus, this review summarizes these elegant achievements based on the multiple reactive sites of different pyrazolone synthons. In addition, important mechanisms and interesting biological investigations relating to the corresponding products are also discussed.

Catalytic enantioselective synthesis of chiral 4-hydroxy 4′-substituted pyrazolones by the vinylogous aldol reaction of pyrazole-4,5-diones with 3-alkylidene-2-oxindoles

Here, a bifunctional quinine-derived benzamide catalyzed direct enantioselective vinylogous aldol reaction between 3-alkylidene-2-oxindoles and pyrazole-4,5-diones has been developed.

Recent Advances in Catalytic Enantioselective Synthesis of Pyrazolones with a Tetrasubstituted Stereogenic Center at the 4-Position

Pyrazolone [2,4-dihydro-3H-pyrazol-4-one] represents one of the most important five-membered nitrogen heterocycles which is present in numerous pharmaceutical drugs and molecules with biological activity. Recently, many catalytic methodologies for the asymmetric synthesis of chiral pyrazolones have been established with great success, specially, for the synthesis of pyrazolones bearing a tetrasubstituted stereocenter at C-4. This review summarizes these excellent research studies since 2018, including representative examples and some mechanistic pathways explaining the observed stereochemistry.

1 Introduction

2 Catalytic Enantioselective Synthesis of Chiral Pyrazolones with a Full Carbon Tetrasubstituted Stereocenter at C-4

3 Catalytic Enantioselective Synthesis of Chiral Pyrazolones with a Quaternary Carbon Stereocenter at C-4 bearing a Heteroatom

4 Catalytic Enantioselective Synthesis of Chiral Spiropyrazolones

5 Conclusion

Recent Advances in Synthesis of Chiral Thioethers

Chiral thioethers is an important class of organosulfur molecules with extensive applications, especially in the field of medicine and organic synthesis. This review discusses the recent progress of synthesis of enantioenriched chiral thioethers and hopes to be helpful for related research in the future. It is summarized from organosulfur compounds-participating organic reaction types, including nucleophilic substitution, cross coupling, sulfa-Michael addition, sulfenylation, asymmetric allylic reaction, asymmetric Doyle-Kirmse reaction, Pummerer-type rearrangement, Smiles rearrangement,^[2,3] Stevens and Sommelet-Hauser rearrangement.