Ene Reaction Of Singlet Oxygen Research Articles

ChemInform Abstract: Z‐3‐Alkylidene‐4,5‐dihydro‐4‐hydroxy‐5‐methyl‐2‐(3H)‐furanones by Regio‐ and Diastereoselective Ene Reaction of Singlet Oxygen (Schenk Reaction) with γ‐Hydroxy Vinylstannanes: An Enantioselective Synthesis of Dihydromahubanolide B.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Regio‐ and Diastereoselective Synthesis of Stannyl Epoxy Alcohols by Direct Hydroxy Epoxidation of Vinylstannanes

The direct synthesis of stannyl epoxy alcohols 3 from vinylstannanes 1 is described. The procedure involves the photooxygenation of Vinylstannanes 1, which proceeds in a highly regioselective manner with predominant hydrogen abstraction geminal to the stannyl group. Subsequent reaction of the resulting hydroperoxides 2 with Ti(OiPr)4 afforded in a one‐pot procedure the epoxy alcohols 3 in high diastereomeric excess, which ranged from 81:19 to greater than 95:5. This convenient and effective method was applied to acyclic and cyclic vinylstannanes as well as to γ‐trydroxyvinylstannane 1e, which was converted into the stannyl epoxy diol 3e. In this novel hydroxy epoxidation of vinylstannanes the regioselectivity of the singlet oxygen ene reaction (Schenck reaction) is controlled by the stannyl group.

Regioselectivity of the Singlet Oxygen Ene Reaction (Schenck Reaction) with Vinylsilanes

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTRegioselectivity of the Singlet Oxygen Ene Reaction (Schenck Reaction) with VinylsilanesWaldemar Adam and Markus J. RichterCite this: J. Org. Chem. 1994, 59, 12, 3335–3340Publication Date (Print):June 1, 1994Publication History Published online1 May 2002Published inissue 1 June 1994https://doi.org/10.1021/jo00091a020RIGHTS & PERMISSIONSArticle Views282Altmetric-Citations20LEARN 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 (801 KB) Get e-Alerts Get e-Alerts

ChemInform Abstract: The Origin of Geminal Regioselectivity in the Ene Reaction of Singlet Oxygen with Substituted Alkenes

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Sensitized Photooxygenation of Dihydropyrimidines. Formation of a Novel Tetraphenyl-5(4H)-pyrimidinone

Abstract Sensitized photooxygenation of 2,4,4,6-tetraphenyl-1,4(or 3,4)-dihydropyrimidine (4a) gave 5-hydroperoxy-2,4,4,6-tetraphenyl-4,5-dihydropyrimidine (5a), which was formed by an ene reaction of singlet oxygen with the 1,4-dihydro form of 4a. Treatment of 5a with silica-gel caused dehydration to give 2,4,4,6-tetraphenyl-5(4H)-pyrimidinone, which is the first synthesized 5-pyrimidinone.

(Z)-3-Alkylidene-4,5-dihydro-4-hydroxy-5-methyl-2-(3H)-furanones by Regio- and Diastereo-selective Ene Reaction of Singlet Oxygen (Schenk Reaktion) with γ-Hydroxy Vinylstannanes: An Enantioselective Synthesis of Dihydromahubanolide B

(Z)-3-Alkylidene-4,5-dihydro-4-hydroxy-5-methyl-2-(3H)-furan-ones (5) were prepared from appropriately substituted propargylic alcohols (1) by a sequence of hydromagnesation to γ-hydroxy vinylstannanes (2), sub- sequent photooxygenation and reduction to stannyl diols (3), iododes- tannylation to iodo diols (4), and finally cyclization by palladium- catalyzed carbonylation (for 5a) or Ni(CO) 2 (PPh 3 ) 2 (for 5b,c). The reaction sequence can be performed enantioselectively by starting with chiral propargylic alcohols. The current approach constitutes a conve- nient four-step synthesis of optically active lactones (5) from readily available starting materials and is applied herein to the preparation of the natural lactone dihydromahubanolide B

ChemInform Abstract: Hydroxy‐Directed Regio‐ and Diastereoselective Ene Reaction of Singlet Oxygen with Chiral Allylic Alcohols.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

ChemInform Abstract: Diastereoselective and Regioselective Photooxygenation of a Chiral Allylic Amine and Its Acyl Derivatives: Stereochemical Evidence for a Steering Effect by the Amino Group in the Ene Reaction of Singlet Oxygen.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Hydroxy-directed regio-diastereoselective ene reaction of singlet oxygen with chiral allylic alcohols

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTHydroxy-directed regio-diastereoselective ene reaction of singlet oxygen with chiral allylic alcoholsWaldemar Adam and Bernd NestlerCite this: J. Am. Chem. Soc. 1993, 115, 12, 5041–5049Publication Date (Print):June 1, 1993Publication History Published online1 May 2002Published inissue 1 June 1993https://doi.org/10.1021/ja00065a013RIGHTS & PERMISSIONSArticle Views654Altmetric-Citations82LEARN 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 (1 MB) Get e-Alerts Get e-Alerts

Diastereoselective and regioselective photooxygenation of a chiral allylic amine and its acyl derivatives: stereochemical evidence for a steering effect by the amino group in the ene reaction of singlet oxygen

Diastereoselective and regioselective photooxygenation of a chiral allylic amine and its acyl derivatives: stereochemical evidence for a steering effect by the amino group in the ene reaction of singlet oxygen

On the origin of geminal regioselectivity in the ene reaction of singlet oxygen with substituted alkenes

The geminal regioselectivity observed in the ene reaction between singlet oxygen and alkenes with anion-stabilizing groups is rationalized on the basis of a perepoxide intermediate, in which in analogy to the nucleophilic attack on protonated epoxides, the perepoxide is opened preferentially at the CO bond weakened by the substituent.

(Z)-3-Methyl-3-penten-2-ol as stereochemical probe for 1,2 versus 1,3 allylic strain in the photooxygenation and epoxidation of chiral allylic alcohols

The importance of 1,2 versus 1,3 allylic strain in hydroxy-directed reactions can be assessed from reactions of (Z)-3-methyl-3-penten-2-ol, which is demonstrated for the ene reaction of singlet oxygen and the epoxidations by m-CPBA and VO(acac) 2 /t-BuOOH; furthermore these results provide insight into transition state geometries for such hydroxy-directed oxygen transfer reactions.

Photooxygenation of chiral allylic alcohols: hydroxy-directed regio- and diastereoselective ene reaction of singlet oxygen

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPhotooxygenation of chiral allylic alcohols: hydroxy-directed regio- and diastereoselective ene reaction of singlet oxygenWaldemar Adam and Bernd NestlerCite this: J. Am. Chem. Soc. 1992, 114, 16, 6549–6550Publication Date (Print):July 1, 1992Publication History Published online1 May 2002Published inissue 1 July 1992https://doi.org/10.1021/ja00042a039RIGHTS & PERMISSIONSArticle Views397Altmetric-Citations66LEARN 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 (286 KB) Get e-AlertsSupporting Info (1)»Supporting Information Supporting Information Get e-Alerts

Solvent effects on the side selectivity of singlet oxygen with α,β unsaturated esters. New evidence for a perepoxide intermediate.

The side selectivity of the ene reaction of singlet oxygen with α, β-unsaturated esters depends on solvent polarity. These results are consonant with the formation of a perepoxide intermediate in the limiting step, of the title reaction.

Dye-sensitized photooxygenation of 2,3-dihydrofurans: competing [2 + 2] cycloadditions and ene reactions of singlet oxygen with a rigid cyclic enol ether system

Singlet oxygen reacts with 2,3-dihydrofuran, 5-methyl-, 4,5-dimethyl-, and 4-carbomethoxy-5-methyl-2,3-dihydrofuran, 5,6-dimethyl-3,4-dihydro-2H-pyran, and 3-methoxy-2-methyl-2-butene (32) in nonpolar and polar aprotic solvents to yield dioxetanes and allylic hydroperoxides, except 32, which gives only allylic hydroperoxides. It is suggested that [2+2] cycloadditions and ene reactions occur via different transition states and intermediates, zwitterions and perepoxides, respectively. Furthermore, the remarkable propensity to dioxetane formationof dihydrofurans compared to that of dihydropyrans and the other enol ethers seems to be due to the rogodoty of the five-membered ring in the transition state and intermediate zwitterion

Photooxygenation of 2-alkenyl substituted chiral oxazolines : Stereochemical evidence favouring the cis effect in the regioselective ene reaction of singlet oxygen with α,β-unsaturated carbonyl derivatives

Photooxygenation of the title compound afforded hydroperoxides through regioselective ene reaction of singlet oxygen at the allylic position proximate to the heterocycle; the lack of diastereoselectivity in these ene reactions is taken as evidence against initial [4+2] cycloaddition of the enophile with the heterodiene.

Do rotational barriers dictate the regioselectivity in the ene reactions of singlet oxygen and triazolinedione with alkenes?

Do rotational barriers dictate the regioselectivity in the ene reactions of singlet oxygen and triazolinedione with alkenes?

ChemInform Abstract: Geminal Selectivity of Singlet Oxygen Ene Reactions. The Nonbonding Large Group Effect.

AbstractIt is shown that the reaction of singlet oxygen with alkenes such as (I) and (IV)‐(VI) leads to products of preferred H‐abstraction from the group geminal to the larger substituent (cf.

Regio‐ and diastereoselective ene reactions of singlet oxygen with dialkyl‐substituted acrylic esters

AbstractPhotooxygenation of methyl (E)‐ and (Z)‐2‐methyl‐4‐phenyl‐2‐pentenecarboxylates (E‐1, Z‐1) afforded the hydroperoxy esters (R*,S*)‐2a and (S*,S*)‐2b through regiospecific and diastereo‐selective ene reaction of singlet oxygen at the α‐methyl group with a diastereomeric ratio (d.r.) of 2a:2b ca. 80:20 for E‐1 and ca. 65:35 for Z‐1. The relative configurations of 2a, b were established by chemical correlation through triphenylphosphine reduction of the allylic hydroperoxy esters 2a, b to the allylic hydroxy esters 4a, b and subsequent catalytic hydrogenation to the literature‐known saturated hydroxy esters 5a, b (from pure 4a) and 5c, d (from pure 4b). The appreciable diastereoselectivity (d.r. ca. 80:20) observed for the E‐1 isomer is explained in terms of the cis effect, by coordinating the allylic hydrogen of the stereogenic C‐4 position to the terminal oxygen of the postulated perepoxide‐like structure.

ChemInform Abstract: Intermediates in the Ene Reactions of Singlet Oxygen and N-Phenyl-1,2,4-triazoline-3,5-dione with Olefins.

The reactions of specifically deuterated butenes with singlet oxygen and N-phenyl-1,2,4-triazoline-3,5-dione are studied.