Stereospecific thermal cycloadditions and catalyzed isomerizations: An organic laboratory project

Pasto, Daniel J.; Duncan, James A.; Silversmith, Ernest F.

doi:10.1021/ed051p277

Cited by 15 publications

(7 citation statements)

References 5 publications

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“…This product was isolated from photolysis experiments and subjected to a series of 2D NMR experiments to confirm structure. The resulting photoproduct was identified as benzo[4,5]thieno[2,3- b ]quinoline-11-carbonitrile 9a (Scheme ), an interesting and unusual heterocycle. − The isolation of this product suggests a sequential, two step photolysis mechanism, in which the first photon isomerizes the phenylnitrile based double bond, and the second photon induces homolysis of the N–O bond of the oxamic acid ester, followed by decarboxylation and radical addition into the adjacent aryl ring. Interestingly, when the reaction was run in deuterated acetonitrile, the product 9a was isolated along with deuterated photoproduct 9b in a 1:1 mixture …”

Section: Resultsmentioning

confidence: 99%

Synthesis and Characterization of a Two Stage, Nonlinear Photobase Generator

et al. 2015

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Amine photobase generators (PBGs) are uncommon yet useful compounds. Rarer still are examples of PBGs that are active at visible wavelengths. We report the synthesis and characterization of new photolabile amine protecting groups that are active under visible light. The new chromophore, benzothiophene imino-phenylacetonitrile (BTIPA), was synthesized in four steps without use of chromatography and found to release any one of several amines upon exposure to 405 nm light. The chromophore was also demonstrated to be useful as a Merrifield synthesis protecting group. Experimental evidence suggests a sequential, two stage photolysis mechanism which leads to a nonlinear response to dose.

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Section: Resultsmentioning

confidence: 99%

Synthesis and Characterization of a Two Stage, Nonlinear Photobase Generator

et al. 2015

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“…General Comments. (H 2 IMes)(pyridine) 2 Cl 2 RuCHPh ( 1a ), (H 2 IMes)(3-bromopyridine) 2 Cl 2 RuCHPh ( 1b ), (±)- endo,exo -bicyclo[2.2.1]hept-5-ene-2,3-dicarboxylic acid dimethyl ester ( 5 ), (±)- endo,exo -(3-benzoylbicyclo[2.2.1]hept-5-en-2-yl)(phenyl)methanone ( 6 ), and 2,4,6-trivinylcyclotriboroxane−pyridine complex were prepared according to the literature methods. 2-Bromobenzaldehyde, 2-bromobenzoyl chloride, 4-(dimethylamino)pyridine and Pd(PPh 3 ) 4 were purchased from Aldrich and were used as received.…”

Section: Methodsmentioning

confidence: 99%

“Second Generation” Ruthenium Carbene Complexes with a cis-Dichloro Arrangement

et al. 2004

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“…The monomers e ndo,exo [2.2.1]bicyclohept‐5‐ene‐2,3‐dicarboxyclic tert‐ butylester ( 1 ),48 5,6‐bis‐(ethoxymethyl)bicyclo[2.2.1]hept‐2‐ene ( 2 ),55 bicyclo[2.2.1]hept‐5‐ene‐2,3‐diylbis(phenylmethanone) ( 3 )56, 57 as well as the initiator RuCl 2 (pyridine) 2 (H 2 IMes)(CHPh)58 (IMes = mesilyten) were prepared according to literature.…”

Section: Methodsmentioning

confidence: 99%

pH and ionic strength responsive polyelectrolyte block copolymer micelles prepared by ring opening metathesis polymerization

Stubenrauch

Voets

Fritz‐Popovski

et al. 2009

J. Polym. Sci. A Polym. Chem.

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Well‐defined amphiphilic block copolymers were prepared by ring opening metathesis polymerization and their stimuli responsive behavior of formed micelles in aqueous solution was investigated. The hydrophobic core of the micelles consists of either a poly[5,6‐bis(ethoxymethyl)bicyclo[2.2.1]hept‐2‐ene]‐block with a glass transition Tg at room temperature or a poly[endo,exo[2.2.1]bicyclohept‐5‐ene‐2,3‐diylbis (phenylmethanone)] with a Tg of 143 °C. For the polyelectrolyte shell, the precursor block poly[endo,exo[2.2.1]bicyclohept‐5‐ene‐2,3‐dicarboxyclic tert‐butylester] was transformed into the free acidic block by cleavage of the tert‐butyl groups using trifluoroacetic acid. Micellar solutions were prepared by dialysis, dissolving the copolymers in dimethyl sulfoxide which was subsequently replaced by water. All polymers form micelles with radii between 10 and 20 nm at a pH‐value below 5, where the carboxylic acid groups are in the protonated state. The block copolymer micelles show a strong increase of the hydrodynamic radius with increasing pH‐value, due to the repulsion among the formed carboxylate anions resulting in a stretching of the polymer chains. In this state, the micelles exhibit responsive behavior to ionic strength where a contraction of the micelles is observed as the carboxylate charges are balanced by sodium ions, whereas no changes of the hydrodynamic radius on addition of salt are observed at low pH. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 1178–1191, 2009

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Stereospecific thermal cycloadditions and catalyzed isomerizations: An organic laboratory project

Cited by 15 publications

References 5 publications

Synthesis and Characterization of a Two Stage, Nonlinear Photobase Generator

Synthesis and Characterization of a Two Stage, Nonlinear Photobase Generator

“Second Generation” Ruthenium Carbene Complexes with a cis-Dichloro Arrangement

pH and ionic strength responsive polyelectrolyte block copolymer micelles prepared by ring opening metathesis polymerization

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