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A Cinchona-derived squaramide catalyzes the reaction between hydroxyindoles and isatins leading to enantioenriched indoles substituted in the carbocyclic ring. The reaction proceeds efficiently with differently substituted isatins, yielding the desired products with excellent regioselectivity, good yields, and high enantiocontrol. Moreover, every position of the carbocyclic ring of the indole can be functionalized by using the appropriate starting hydroxyindole. The OH group was removed smoothly upon hydrogenolysis of the corresponding triflate.
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http://dx.doi.org/10.1021/acs.orglett.7b00354 | DOI Listing |
Chem Commun (Camb)
September 2025
CSIR-Central Drug Research Institute Lucknow, 226031, India.
α-Diazo compounds have long been recognized as versatile reagents in organic synthesis, traditionally employed in metallocarbene chemistry. Recent advances have expanded their scope beyond conventional carbene-based transformations, leading to diverse applications in heterocycle synthesis and functionalization strategies. This review highlights the evolution of α-diazo compounds as key reagents in modern synthetic methodologies, focusing on their unique reactivity patterns, including cycloadditions, homologations, ring expansions, and carbene-free functionalizations.
View Article and Find Full Text PDFNature
August 2025
Chemistry Research Laboratory, Department of Chemistry, University of Oxford, 12 Mansfield Road, Oxford, UK.
The enantioselective construction of small ring carbocycles provides organic chemists with an enduring challenge. Despite their commercial importance, enantioselective synthetic routes towards alkylidenecyclopropanes (ACPs), a class of small ring carbocycles, remain underdeveloped. Importantly, ACPs can be converted into cyclopropanes, a common feature in drug molecules (e.
View Article and Find Full Text PDFNat Synth
December 2024
Department of Chemistry, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA.
Enantioselective dehydrogenation of prochiral C-H bonds could provide a powerful method for constructing chiral centers attached to synthetically versatile vinyl groups. Herein, we describe the realization of enantioselective β,γ-dehydrogenation of cycloalkyl amides enabled by chiral oxazoline-pyridone ligands to afford a wide range of highly elaborated carbocycles with exceptional enantioselectivity (>99% ee). Notably, the resulting chiral β,γ-unsaturated carbocycles are difficult to access via inverse electron demand Diels-Alder reaction.
View Article and Find Full Text PDFJ Am Chem Soc
August 2025
Department of Chemistry, The University of Texas at Austin, Austin, Texas 78712, United States.
We report herein the first total synthesis of (+)-pierisketone B, a bioactive diterpene that possesses a unique tetracyclic 7/5/6/5 carbocyclic framework that is punctuated with numerous stereocenters, two of which are quaternary and five of which are contiguous. The synthesis features an unusual Pauson Khand cyclization to generate the bridged tricyclic core. Creation of the requisite -fused hydrindanone moiety was achieved by hydroxyl directed hydrogenation of an allylic alcohol, and the A-ring of the natural product was formed by a Mukaiyama aldol reaction followed by a cyclization involving addition of a vinyl anion to a proximal ketone group.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
August 2025
School of Chemistry, University of Bristol, Cantock's Close, BS8 1TS, Bristol, UK.
Saturated carbocycles are common motifs in natural products and pharmaceuticals, and so methods for their construction, particularly with high diastereo- and enantiocontrol, are of high importance. Lithiation-borylation has emerged as powerful methodology for the stereocontrolled construction of acyclic carbon chains but has not previously been used for the stereocontrolled synthesis of carbocycles. Herein, we report that benzylic diethylcarbamates with a tethered vicinal bis-boronic ester moiety can be deprotonated with lithium amide bases, resulting in cyclization and 1,2-metallate rearrangement to give carbocycles.
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