Photocycloaddition Of Alkenes Research Articles

Following reaction paths in organic photochemistry: The special role of surface crossings

Abstract

Furans from Novel [3 + 2] Photocycloaddition of Alkenes to 2-(1-Alkynyl)cyclohexenones

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTFurans from Novel [3 + 2] Photocycloaddition of Alkenes to 2-(1-Alkynyl)cyclohexenonesPaul Margaretha, William C. Agosta, and Stefan ReichowCite this: J. Org. Chem. 1994, 59, 18, 5393–5396Publication Date (Print):September 1, 1994Publication History Published online1 May 2002Published inissue 1 September 1994https://doi.org/10.1021/jo00097a049RIGHTS & PERMISSIONSArticle Views331Altmetric-Citations28LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (564 KB) Get e-AlertsSupporting Info (1)»Supporting Information Supporting Information Get e-Alerts

Tetrasubstituted furans from photocycloaddition of alkenes to 2-(1-alkynyl)cyclohexenones

Photocycloaddition of 2-(1-alkynyl)cyclohexenones 1 and 2 with alkenes 3 and 4 furnishes tetrasubstituted furans 5–8 as the only isolated products; a suggested mechanism leads from the alkyl propynyl biradical 12 to carbene 13, which then closes to the furan.

ChemInform Abstract: Stereochemistry and Mechanism of the (2 + 2) and (4 + 2) Photocycloaddition of Alkenes and Dienes to Pummerer′s Ketone.

AbstractPummerer's ketone (I) undergoes (4 + 2) cycloaddition to furan (II) and (2 + 2) cycloaddition to the alkenes (IV) and (VI) via a common intermediate, namely the short‐lived twisted triplet excited state of (I).

Stereochemistry and mechanism of the [2 + 2] and [4 + 2] photocycloaddition of alkenes and dienes to pummerer's ketone

Irradiation of Pummerer's ketone (PK) in furan gave the trans-fused [4 + 2] cycloadducts 2 and 3, whose structures were determined by their 1H NMR spectra and confirmed by X-ray crystallography. Irradiation of PK in the presence of tetramethylethylene (TME) gave cycloadduct 4 and with 1,1-dimethoxyethylene (DME) gave [2 + 2] cycloadducts 5,6 and 7, respectively. The X-ray crystal structures of 4—7 show that the four- and six-membered rings of 4 and 7 are trans-fused, and 5 and 6 are cis-fused, respectively. Differential quenching of the formation of cycloadducts 2–5 and 7 by the free radical TEMPO was observed. Formation of cycloadducts 2–4 was also quenched differentially by O 2. A short lived (15 nsec) transient observed on nanosecond flash photolysis of PK is suggested to be a highly twisted triplet excited state, which is the likely precursor of both [4 + 2] and [2 + 2] adducts. It is proposed that stepwise addition of furan and alkenes to PK triplets gives triplet biradicals, which can be intercepted by TEMPO and O 2 , and that these reactions probably do not involve a ground state trans-cyclohexenone intermediate.

Photochemistry of ketones in solutions. 70. Identification of the reactive electronic excited state in the photocycloaddition of alkenes to cyclic enones

Photochemistry of ketones in solutions. 70. Identification of the reactive electronic excited state in the photocycloaddition of alkenes to cyclic enones

Photocycloaddition of alkenes and acetylenes to fluoro-substituted benzene derivatives

Photocycloaddition of alkenes and acetylenes to fluoro-substituted benzene derivatives