The presence of an alkenyl substituent on the terminal epoxide of a polyepoxide substrate enhances the yield of all-endo-regioselective tandem oxacyclization to trans-syn-trans-fused polycyclic ethers. For a substrate in which the epoxide and alkene functional groups are separated by two methylene substituents, a novel bromonium ion-induced endo-regioselective cyclization to bromooxepane is also described. [reaction: see text]
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1021/ol048212e | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Assembly of Pyrenes through a Quadruple Photochemical Cascade: Blocking Groups Allow Diversion from the Double Mallory Path to Photocyclization at the Bay Region.
J Am Chem Soc
December 2024
Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida 32306, United States.
We present a six-step cascade that converts 1,3-distyrylbenzenes (-stilbenes) into nonsymmetric pyrenes in 40-60% yields. This sequence merges photochemical steps, ,-alkene isomerization, a 6π photochemical electrocyclization (Mallory photocyclization); the new bay region cyclization, with two radical iodine-mediated aromatization steps; and an optional aryl migration. This work illustrates how the inherent challenges of engineering excited state reactivity can be addressed by logical design.
View Article and Find Full Text PDFPhotoinduced Concerted Fragmentation of Alkyl -Phthalimidoyl Oxalates: Mechanisms and Applications.
Org Lett
December 2024
School of Pharmaceutical and Chemical Engineering and Institute for Advanced Studies, Taizhou University, Taizhou 318000, China.
In this work, we used experiments and density functional theory calculations to investigate the mechanism and driving forces of the reductive fragmentation of NHPI esters. Mechanistic studies suggest that the fragmentation behavior of the NHPI ester is influenced not only by the electronic nature of the substituent group but also by the stability of the radical intermediate. To further investigate this transformation, we next examined the aminoalkoxycarbonylation of alkenes using alkyl -phthalimidoyl oxalates.
View Article and Find Full Text PDFMechanism-Guided Development of Bifunctional Cyclooctenes as Active, Practical, and Light-Gated Bromination Catalysts.
Chemistry
December 2024
Hokkaido University, Institute for Catalysis, Kita21, Nishi10, Kita, 001-0021, Sapporo, JAPAN.
Most molecular catalysts have been developed employing polar functional groups as catalytic sites. However, the use of non-polar functional groups for catalysis has received less attention due to their modest molecular interactions while the bioorthogonal reactivity of non-polar alkenes as substrates is frequently used in click chemistry. In this study, we conducted mechanistic studies on the catalysis of trans-cyclooctene (TCO) derivatives with the strained olefin as the catalytic site using kinetic and computational analyses to aid the design of more active olefin catalysts.
View Article and Find Full Text PDFIodine-Promoted C-H Bond Amination Reaction for the Synthesis of Fused Tricyclic Heteroarenes.
J Org Chem
December 2024
Department of Chemistry, 107 Physical Sciences, Oklahoma State University, Stillwater, Oklahoma 74078, United States.
Fused heterocyclic scaffolds, such as benzimidazoles or larger ring systems containing a benzimidazole fragment, are frequently encountered in pharmaceutical compounds and other biologically active molecules. While there are many examples of N9- and/or C3-substituted 9-benzo[4,5]imidazo[2,1-][1,2,4]triazoles, current examples of the regioselective preparation of N1-substituted 1-benzo[4,5]imidazo[2,1-][1,2,4]triazoles are limited to N1-aryl substituted compounds, which also contain a C3-substituent. Here, we report an iodine-promoted C-H bond amination reaction that allows the selective preparation of 1-benzo[4,5]imidazo[2,1-][1,2,4]triazoles with a variety of aryl and alkyl N1-substituents.
View Article and Find Full Text PDFB(CF)-Catalyzed Regiodivergent Thioetherifications of Alkenes via Thiiranium Intermediates: Experimental and Computational Insights.
Chemistry
December 2024
Cardiff Catalysis Institute, School of Chemistry, Cardiff University, Translational Research Hub, Maindy Road, Cathays, Cardiff, Cymru/Wales, CF24 4HQ, UK.
Precise control of selective alkene functionalization is a continuing challenge in the chemical community. In this study, we develop a substitution-controlled regiodivergent thioetherification of di- or trisubstituted alkenes using 10 mol % tris(pentafluorophenyl)borane [B(CF)] as a catalyst and N-thiosuccinimide as a sulfenylating reagent. This metal-free borane catalyzed C-S bond forming method is utilized for a Csp-H sulfenylation reaction to synthesize an array of diphenylvinylsulfide derivatives with good to excellent yields (25 examples, up to 91 % yield).
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!