Cycloaddition reactions of stilbene-electron-poor-alkene exciplexes

Green, B. S.; Rejtő, Miriam; Johnson, Douglas E.; Hoyle, Charles E.; Simpson, James T.; Correa, Paul E.; Ho, Tong‐Ing; Mccoy, F.; Lewis, Frederick D.

doi:10.1021/ja00506a031

Cited by 27 publications

(15 citation statements)

References 5 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Hence, employing asymmetric photoreaction is expedient for experimentally differentiating ECT from EX by observing the change in the stereochemical outcome. We employed a chiral version of the well-established photocycloaddition of (E)-ST to alkyl fumarate, 29 where (R)-1-methylpropyl was chosen as the simplest chiral alkyl group. 35,36 In this system, the intervention of ECT versus EX was unambiguously sorted out by analysing the diastereoselectivities of the cyclobutanes obtained upon excitation at different wavelengths, as detailed below.…”

Section: Asymmetric Photoreactions Of the Intermolecular C-t Complex mentioning

confidence: 99%

Charge-transfer excitation: unconventional yet practical means for controlling stereoselectivity in asymmetric photoreactions

Mori

Inoue

2013

Chem. Soc. Rev.

View full text Add to dashboard Cite

In chiral donor-acceptor (D-A) systems, irradiation wavelength plays vital roles in determining the photochemical consequences. Selective excitation of a D-A complex at the charge-transfer (C-T) band affords an excited C-T complex (ECT), while the local-band excitation of D or A may lead to the formation of a conventional exciplex (EX) upon subsequent interaction with the D-A partner. These two excited species, generated from the same D-A pair, may be categorized formally as excited complexes or exciplexes, but should be distinguished, provided that they significantly differ in structure and reactivity. Indeed, ECT and EX exhibit distinctly different temperature-dependent photophysical and photochemical behaviours, which are assignable to the differences in relative stability, conformational flexibility and/or solvation properties. Fine-tuning excitation wavelength further enabled us to discriminate stereoisomeric intramolecular C-T complexes through preferential excitation, as C-T complexes are generally composed of an ensemble of various geometries. Besides temperature and solvent polarity, the excitation wavelength was shown to be employed as an unconventional yet practical tool for critically controlling the chemo-, regio- and stereoselectivities in molecular and supramolecular photochemistry.

show abstract

Section: Asymmetric Photoreactions Of the Intermolecular C-t Complex mentioning

confidence: 99%

Charge-transfer excitation: unconventional yet practical means for controlling stereoselectivity in asymmetric photoreactions

Mori

Inoue

2013

Chem. Soc. Rev.

View full text Add to dashboard Cite

show abstract

“…In contrast, each of the reactions of 1,1-diphenylethene (2b) and a-methylstyrene (2d) yields the regioisomeric cylcobutane derivatives 8b,c and 12b (Schemes 3 and 5, resp.). These reactions suggest that the existence of a maximum secondary orbital overlap influences the stereochemistry of the additions [13]. The Figure demonstrates the overlap between PhÀC(3) of the trans-stilbene (2a) and PhÀC(5) of the B-complex 1c.…”

mentioning

confidence: 93%

Photocycloaddition of Some Difluoro(aminoenonato)boron Complexes with Arylalkenes

Itoh

Okazaki

Chow

2004

Helvetica Chimica Acta

View full text Add to dashboard Cite

The photocycloaddition of some difluoro[(methylamino-kN)alkenonato-kO]boron complexes 1 with arylalkenes 2 is discussed. The resulting [2 2] photoaddition gave the cyclobutane and azetidine derivatives (Schemes 1, 3, and 5). Rearrangements of the cyclobutane gave 1,5-diketones derivatives (Schemes 2, 4, and 5). The yields of the photoadducts were governed by the reduction and oxidation potentials. Furthermore, the configurations of the products established high regio-and stereoselectivity, suggesting the presence of a singlet exciplex. The reactivity and the stereochemistry were rationalized by means of FMO (frontier molecular orbital) calculations.

show abstract

“…oxetane. 6 Among the cyclobutanes, the m-isomer is favored due to the extensive p,p-interactions between the phenyl and ester moieties. 7 Irradiation at the CT band affords the same products in a similar ratio.…”

mentioning

confidence: 99%

“…7 Irradiation at the CT band affords the same products in a similar ratio. 6 Diastereodifferentiating photocycloaddition of 1E to di-L-bornyl and methyl L-bornyl fumarates has also been investigated but only through the direct irradiation. 8 Recently, we have revealed that the conventional exciplex and the excited CT complex are distinctly different in structure and reactivity.…”

mentioning

confidence: 99%

See 1 more Smart Citation

Pressure control of diastereodifferentiating [2 + 2] photocycloaddition of (E)-stilbene to chiral fumarate upon direct and charge-transfer excitationElectronic supplementary information (ESI) available: pressure effect on the product ratio 4/3. See http://www.rsc.org/suppdata/cc/b4/b404555f/

et al. 2004

View full text Add to dashboard Cite

show abstract

Cycloaddition reactions of stilbene-electron-poor-alkene exciplexes

Cited by 27 publications

References 5 publications

Charge-transfer excitation: unconventional yet practical means for controlling stereoselectivity in asymmetric photoreactions

Charge-transfer excitation: unconventional yet practical means for controlling stereoselectivity in asymmetric photoreactions

Photocycloaddition of Some Difluoro(aminoenonato)boron Complexes with Arylalkenes

Pressure control of diastereodifferentiating [2 + 2] photocycloaddition of (E)-stilbene to chiral fumarate upon direct and charge-transfer excitationElectronic supplementary information (ESI) available: pressure effect on the product ratio 4/3. See http://www.rsc.org/suppdata/cc/b4/b404555f/

Contact Info

Product

Resources

About