Asymmetric oxaziridination catalyzed by cinchona alkaloid derivatives containing sulfide

Asymmetric synthesis of spiro[4H-chromene-3,3'-oxindoles] via a squaramide-organocatalytic three-component cascade Knoevenagel/Michael/cyclization sequence

Asymmetric synthesis of spiro[4H-chromene-3,3'-oxindole] derivatives was realized through an organocatalytic cascade Knoevenagel/Michael/cyclization reaction using a quinidine-derived squaramide. Under the optimized conditions, the reactions of isatins, malononitrile, and sesamol yield the desired spirooxindoles in good yields (75-87%) and moderate to high ee values (up to 90% ee).

Developing flow photo-thiol–ene functionalizations of cinchona alkaloids with an autonomous self-optimizing flow reactor

Continuous flow photo-thiol–ene reactions on cinchona alkaloids with a variety of organic thiols have been developed using enabling technologies such as a self-optimizing flow photochemical reactor.

Direct Synthesis of N,N-Disubstituted Formamides by Oxidation of Imines Using an HFIP/UHP System

The straightforward synthesis of N,N-disubstituted formamides using a combination of 1,1,1,3,3,3-hexafluoroispropanol (HFIP) and H₂O₂ is described. The unique features of HFIP allowed the utilization of a green oxidant such as H₂O₂, and the products, arising from an oxidation-rearrangement sequence, were obtained in good to high yields under smooth reaction conditions.

Synergistic Ammonium (Hypo)Iodite/Imine Catalysis for the Asymmetric α-Hydroxylation of β-Ketoesters

The synergistic use of chiral bifunctional ammonium iodide catalysts in combination with simple catalytically relevant aldimines allows for an unprecedented asymmetric α-hydroxylation reaction of β-ketoesters using H2O2. The reaction proceeds via in situ formation of a hypervalent iodine species, which then reacts with the used aldimine to generate an activated electrophilic oxygen transfer reagent.

C6′ steric bulk of cinchona alkaloid enables an enantioselective Michael addition/annulation sequence toward pyranopyrazoles

A C6′ silyloxyl quinine catalyzed asymmetric Michael addition/annulation cascade between pyrazolones and enynones was developed.

A novel complexity-to-diversity strategy for the diversity-oriented synthesis of structurally diverse and complex macrocycles from quinine

Recent years have witnessed a global decline in the productivity and advancement of the pharmaceutical industry. A major contributing factor to this is the downturn in drug discovery successes. This can be attributed to the lack of structural (particularly scaffold) diversity and structural complexity exhibited by current small molecule screening collections. Macrocycles have been shown to exhibit a diverse range of biological properties, with over 100 natural product-derived examples currently marketed as FDA-approved drugs. Despite this, synthetic macrocycles are widely considered to be a poorly explored structural class within drug discovery, which can be attributed to their synthetic intractability. Herein we describe a novel complexity-to-diversity strategy for the diversity-oriented synthesis of novel, structurally complex and diverse macrocyclic scaffolds from natural product starting materials. This approach exploits the inherent structural (including functional) and stereochemical complexity of natural products in order to rapidly generate diversity and complexity. Readily-accessible natural product-derived intermediates serve as structural templates which can be divergently functionalized with different building blocks to generate a diverse range of acyclic precursors. Subsequent macrocyclisation then furnishes compounds that are each based around a distinct molecular scaffold. Thus, high levels of library scaffold diversity can be rapidly achieved. In this proof-of-concept study, the natural product quinine was used as the foundation for library synthesis, and six novel structurally diverse, highly complex and functionalized macrocycles were generated.

N-Sulfonyl α-imino ester-derived chiral oxaziridines: catalytic asymmetric synthesis and application as a modular chiral organic oxidant

A novel class of chiral N-sulfonyl oxaziridines is catalytically prepared and introduced for use as highly reactive and enantiospecific oxidants.

Enantioselective organocatalytic oxidation of ketimine

with promoted the enantioselective organocatalytic oxidation of to afford oxaziridines bearing a tetrasubstituted carbon stereogenic center in high yields with up to 87% ee.