[reaction: see text] The oxa-di-pi-methane (ODPM) photochemical rearrangement, a triplet-sensitized sigmatropic 1,2-acyl shift of beta,gamma-enones, was successful utilizing methyl and heptyl 1-aza-3-carboalkoxybicyclo[2.2.2]oct-2-en-5-ones (quinuclidinones) as the photoprecursors. The cyclopropane of the heptyl ester tricyclic photoproduct could be opened with lithium dimethylcuprate or via hydrogenolysis to produce the corresponding pyrrolizidinone skeletons.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1021/ol035202p | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Intramolecular Photocycloaddition of 4-Substituted 7-(4'-Alkenyloxy)-1-indanones and Ensuing Reaction Cascades.
J Org Chem
March 2025
Department Chemie and Catalysis Research Center (CRC), Technische Universität München, Lichtenbergstr. 4, 85747 Garching, Germany.
4-Substituted 7-(4'-alkenyloxy)-1-indanones were prepared from the respective substituted aryl propanoic acids and subjected to UV-A irradiation (λ = 350 or 366 nm). While the 4-chloro compound was directly converted at λ = 366 nm into a pentacyclic product (47% yield) by a three-photon cascade process, the oxygenated substrates reacted in trifluoroethanol at λ = 350 nm by a two-photon cascade, involving an photocycloaddition, a thermal disrotatory ring opening, and a [4π] photocyclization (six examples, 67-82% yield). An ensuing photochemical di-π-methane rearrangement of the latter products was achieved by irradiation at λ = 350 nm in toluene (five examples, 36-70% yield).
View Article and Find Full Text PDFPolysilazane-Coated Films Achieving Record-High Moisture Barrier Performance with Sub-10 Seconds Densification Using High-Power VUV Irradiation.
Adv Sci (Weinh)
February 2025
Innovation Center for Organic Electronics (INOEL), Yamagata University, Arcadia 1-808-48, Yonezawa, Yamagata, 992-0119, Japan.
An ultra-high moisture barrier compact SiN film can be achieved from solution-processed perhydropolysilazane (PHPS) through vacuum ultraviolet (VUV) light exposure. This study investigates the photochemical reactions and photo-densification of PHPS-based barrier films under varying VUV light intensities, focusing on their effects on barrier performance. Photo-dehydrogenation of PHPS, involving N─H and Si─H bond cleavage, is efficient and unaffected by light intensity.
View Article and Find Full Text PDFA Photo-Smiles Rearrangement: Mechanistic Investigation of the Formation of Blatter Radical Helicenes.
J Org Chem
February 2025
Centre of Molecular and Macromolecular Studies, Polish Academy of Sciences, 90-363 Łódź, Poland.
Photocyclization of 8-aryloxy-3-phenylbenzo[][1,2,4]triazines leads to helicene radicals. Structural analysis of radicals forms by two-dimensional correlation nuclear magnetic resonance methods demonstrated that the photocyclization involves a Smiles rearrangement and exclusive formation of a single rearranged product for all substrates. Density functional theory investigations indicate that the mechanism requires the T state with (n, π*) character localized on the benzo[][1,2,4]triazine (BT) fragment and at least one occupied π molecular orbital (MO) localized on the aryloxy fragment with an energy that is higher than that of the n MO.
View Article and Find Full Text PDFPhototransposition of Indazoles to Benzimidazoles: Tautomer-Dependent Reactivity, Wavelength Dependence, and Continuous Flow Studies.
Angew Chem Int Ed Engl
February 2025
UC Berkeley: University of California Berkeley, Department of Chemistry, Latimer Hall, 94720, Berkeley, UNITED STATES OF AMERICA.
Herein, we report a detailed investigation of the photomediated transformation of indazoles to benzimidazoles through a nitrogen-carbon transposition. This phototransposition is known to occur in low yield when 1H-indazoles are subjected to high-energy UVC irradiation. The 2H-tautomer of indazole absorbs light more strongly than the 1H-tautomer at longer wavelengths.
View Article and Find Full Text PDFPhotochemical Conversion of Indazoles into Benzimidazoles.
Angew Chem Int Ed Engl
January 2025
RWTH Aachen University: Rheinisch-Westfalische Technische Hochschule Aachen, Institute of Organic Chemistry, GERMANY.
Fragment-based drug discovery relies on preparing diverse libraries of advanced building blocks, often incorporating heteroaromatic motifs. Altering the core of heteroaromatics to maximise library diversity typically requires de novo synthesis of each system. This can be often challenging when specific substitution patterns are needed.
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!