Photochemical rearrangement reactions of bicyclic molecules that contain a cyclopropane ring

The liquid phase photolysis of undiluted di-n-butyl terephthalate yields 1-butene and carboxylic acid end groups as a result of a Norrish Type II photochemical rearrangement reaction. Quantum yields for the production of these two products have been determined and found to be [Formula: see text] and [Formula: see text] in vacuum and [Formula: see text] and [Formula: see text] in air.

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Unusual dependence of the quantum yields of photochemical rearrangement of substituted 8-phenyl-3,5,10-trioxa-9-azabicyclo[5,3,0]dec-8-enes to 2-substituted 6-phenyl-7-formyl-2,4,5,8-tetrahydro-1,3-dioxa-5-azocines on exo-endo arrangement

Journal für Praktische Chemie ◽

10.1002/prac.19863280322 ◽

1986 ◽

Vol 328 (3) ◽

pp. 445-448 ◽

Cited By ~ 6

Author(s):

Ľ. Fišera ◽

V. Oremus ◽

L. Štibrányi ◽

P. Zálupský ◽

H.-J. Timpe ◽

...

Keyword(s):

Quantum Yields ◽

Photochemical Rearrangement

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p-Hydroxyphenacyl photoremovable protecting groups — Robust photochemistry despite substituent diversity

Canadian Journal of Chemistry ◽

10.1139/v10-143 ◽

2011 ◽

Vol 89 (3) ◽

pp. 364-384 ◽

Cited By ~ 21

Author(s):

Richard S. Givens ◽

Kenneth Stensrud ◽

Peter G. Conrad ◽

Abraham L. Yousef ◽

Chamani Perera ◽

...

Keyword(s):

Aqueous Media ◽

Protecting Groups ◽

Quantum Yields ◽

Photochemical Rearrangement ◽

Favorskii Rearrangement ◽

Leaving Group ◽

Predominant Form ◽

Photoremovable Protecting Groups ◽

Conjugate Base ◽

Modest Effect

A broadly based investigation of the effects of a diverse array of substituents on the photochemical rearrangement of p-hydroxyphenacyl esters has demonstrated that common substituents such as F, MeO, CN, CO2R, CONH2, and CH3 have little effect on the rate and quantum efficiencies for the photo-Favorskii rearrangement and the release of the acid leaving group or on the lifetimes of the reactive triplet state. A decrease in the quantum yields across all substituents was observed for the release and rearrangement when the photolyses were carried out in buffered aqueous media at pHs that exceeded the ground-state pKa of the chromophore where the conjugate base is the predominant form. Otherwise, substituents have only a very modest effect on the photoreaction of these robust chromophores.

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Derivatives of tetrahydro-2H-pyridine from photorearranged cycloadducts of nitrile oxides

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19900512 ◽

1990 ◽

Vol 55 (2) ◽

pp. 512-523 ◽

Cited By ~ 7

Author(s):

Lubor Fišera ◽

Vladimír Ondruš ◽

Hans-Joachim Timpe

Keyword(s):

Reaction Mechanism ◽

Double Bond ◽

Quantum Yields ◽

Dipolar Cycloaddition ◽

Mercury Lamp ◽

Reaction Sequence ◽

Nitrile Oxides ◽

Photochemical Rearrangement ◽

Benzene Rings ◽

Derivatives Of

1,3-Dipolar cycloaddition of methoxycarbonylnitrile, furannitrile and substituted benzene nitrile oxides (X = 4-CH3, 4-OCH3, 3-OCH3, 4-Cl, 3-Cl, 2,4-diCl, 4-F) to dimethyl 7-(diphenylmethylene)bicyclo[2.2.1]hept-2-ene-5,6-dicarboxylate (XII) led exclusively to exo cycloadducts IV, on irradiation with a low-pressure mercury lamp afforded the required 4-substituted derivatives of dimethyl 2,2-diphenyl-5-formyl-3-azabicyclo[4.3.0]nona-4,9-diene-7,8-dicarboxylate (XI) as sole products. Selectivity of the photorearrangement of isoxazolines IV to enaminoaldehydes XI is due to a stabilization of the biradical VII by the overlap of the radical-electron with π-electrons of the C=C double bond and by two benzene rings. Quantum yields of the photorearrangement, established from the deficit of the starting IV, were found to be greater than those for the analogous oxabicyclic derivatives XVI. The reaction mechanism is proposed and the dependence on various solvents is pointed out; this reaction sequence, viz. the 1,3-dipolar cycloaddition followed by a photochemical rearrangement provides a new method for obtaining derivatives of tetrahydro-2H-pyridine from the well available cyclopentadiene.

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Highly Luminescent 4-Pyridyl-Extended Dithieno[3,2-b:2′,3′-d]phospholes

10.26434/chemrxiv.12455357.v1 ◽

2020 ◽

Author(s):

Thomas Baumgartner ◽

Paul Demay-Drouhard

Keyword(s):

Electrochemical Properties ◽

Quantum Yields

The unexpectedly challenging synthesis of 4-pyridyl-extended dithienophospholes is reported. The optical and electrochemical properties of the phosphoryl-bridged species were studied experimentally and computationally, and their properties compared to their non-P-bridged congeners. The 4-pyridyl-extended dithieno-phospholes display quantitative luminescence quantum yields in solution.

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Highly Luminescent 4-Pyridyl-Extended Dithieno[3,2-b:2′,3′-d]phospholes

10.26434/chemrxiv.12455357 ◽

2020 ◽

Author(s):

Thomas Baumgartner ◽

Paul Demay-Drouhard

Keyword(s):

Electrochemical Properties ◽

Quantum Yields

The unexpectedly challenging synthesis of 4-pyridyl-extended dithienophospholes is reported. The optical and electrochemical properties of the phosphoryl-bridged species were studied experimentally and computationally, and their properties compared to their non-P-bridged congeners. The 4-pyridyl-extended dithieno-phospholes display quantitative luminescence quantum yields in solution.

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