Reversible intramolecular photodimerization of 1,3-bis(.alpha.-naphthyl)propane

Chandross, Edwin A.; Dempster, Carol J.

doi:10.1021/ja00706a049

Cited by 50 publications

(7 citation statements)

References 2 publications

(2 reference statements)

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“…The two facing benzene ring protons of syn - 4a and syn - 4c , and the vinylic protons of anti - 4a and 4c showed upfield shifts relative to those of the other corresponding diastereomers due to the shielding effect caused by the benzene ring. Their bridgehead methine and vinylic protons showed agreeable 1 H NMR chemical shifts to those of a similar system. , Syn preference of the [4 + 4] adduct originated from the effective π-orbital overlap for the exciplex formation between the two facing naphthalene rings . When 1a − d were irradiated under bubbling of oxygen, novel trapping products, 1,8-epidioxides 5a − d , were obtained as a single diastereomer with the suppressed yield of the other cycloadducts (isolated yields are summarized in Table ).…”

Section: Resultsmentioning

confidence: 85%

Trapping of 1,8-Biradical Intermediates by Molecular Oxygen in Photocycloaddition of Naphthyl-N-(naphthylcarbonyl)carboxamides; Formation of Novel 1,8-Epidioxides and Evidence of Stepwise Aromatic Cycloaddition

et al. 2000

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The photocycloaddition reaction of naphthyl-N-(naphthylcarbonyl)carboxamides (1) was examined under argon and oxygen atmospheres. In addition to the [2 + 2] and [4 + 4] cycloadducts, 3 and 4, respectively, novel 1,8-epidioxides (5) were formed under oxygen atmosphere. The transient absorption at lambda max of 360 nm with the lifetime of 360 ns was observed by laser flash photolysis of 1c and was interpreted as the absorption of biradical intermediate 2. On the basis of the anti stereochemistry of 5, which was different from that of the major [4 + 4] cycloadducts, syn-4, it was deduced that equilibrium between biradical intermediates syn-2 and anti-2 would exist. Retro [2 + 2] cycloaddition of 3 was responsible for the efficient trapping of the biradical intermediate with molecular oxygen. The photocycloaddition of the anthryl derivatives, 9-anthryl-N-(methylethyl)-N-(naphthylcarbonyl)carboxamides (7), afforded the [4 + 4] cycloadducts (8) exclusively in a quantitative yield even under oxygen atmosphere. The absence of trapping with molecular oxygen was interpreted to be due to the lack of retro [4 + 4] cycloaddition of 8.

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Section: Resultsmentioning

confidence: 85%

Trapping of 1,8-Biradical Intermediates by Molecular Oxygen in Photocycloaddition of Naphthyl-N-(naphthylcarbonyl)carboxamides; Formation of Novel 1,8-Epidioxides and Evidence of Stepwise Aromatic Cycloaddition

et al. 2000

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“…To investigate the intramolecular anthracene photodimerization process of 3 , a dilute solution of 3 (10 −4 M ) in degassed CDCl 3 was irradiated with 350 nm UV light 12. 13 After irradiation for 1 h, the 1 H NMR spectrum of 3 in CDCl 3 showed the disappearance of the anthracene peaks from 7.20–8.20 ppm and the appearance of a new peak (singlet) around 4.40 ppm (Figure 3 b).…”

Section: Methodsmentioning

confidence: 99%

P190: Audit of the sonographic estimation of fetal weight based on fetal abdominal circumference

Pascall

Broadhurst

Cietak

2003

Ultrasound Obstet Gynecol

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Guests in a gated community: Introduction of two anthracene groups into a linker in a hemicarcerand creates a new type of photochemically controlled gated hemicarcerand. The reversible opening and closing of the “gate” of the host is controlled photochemically. The encapsulation and release of the guest molecules such as 1,4‐dimethoxybenzene is controlled by irradiation with light of different wavelengths.

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“…179 Naphthalene and its derivatives are known to undergo [4+4] photodimerization to yield trans (major) and cis (minor) photoadducts which, in a subsequent [2+2] cycloaddition step, can give rise to cubane-like structures. 180,181 Efforts in controlling this reaction initially focused on using micellar environments. 182 Wu and co-workers have since shown that encapsulation of two naphthalene moieties by CB [8] exerts stringent control of the interor intra-molecular photodimerization of 2-naphthoates, strongly favoring the formation of the cis photodimer.…”

Section: Templated [4p+4p] Photocyclization Reactionsmentioning

confidence: 99%