123620-27-9Relevant articles and documents
Substantial 2H-magnetic isotope effects on the diastereoselectivity of triplet photocycloaddition reactions
Griesbeck, Axel G.,Bondock, Samir,Cygon, Peter
, p. 9016 - 9017 (2003)
Magnetic isotope effects (MIE) on the diastereoselectivity of the triplet [2+2]-photocycloaddition of benzaldehyde with 2,3-dihydrofuran are described for four substrate combinations. The MIE results from H/D exchange at the reactive carbons of either the
The diastereoselectivity of the Paternò-Büchi reaction between 2,3-dihydrofuran and aromatic carbonyl compounds in organized medium
D'Auria, Maurizio,Pellegrino, Francesco,Viggiani, Licia
, p. 69 - 75 (2016/05/19)
The Paternò-Büchi reaction between benzaldehyde and 2,3-dihydrofuran can be performed within the cavity of NaY zeolite. An increased stereoselectivity has been observed. When the reaction was performed with substituted benzaldehyde derivatives, different
Temperature and viscosity dependence of the spin-directed stereoselectivity of the carbonyl-alkene photocycloaddition
Griesbeck, Axel G.,Bondock, Samir,Gudipati, Murthy S.
, p. 4684 - 4687 (2007/10/03)
The multiplicity of the excited state controls the product distribution in the formation of endolexo-oxetane 3 in the photocycloaddition of aldehydes 1 (R = Ph, Et, Me, iBu) with dihydrofuran 2 (Paterno-Buechi reaction). Whether the singlet or triplet cha
Stereoselectivity of Triplet Photocycloadditions:1 Diene-Carbonyl Reactions and Solvent Effects
Griesbeck, Axel G.,Buhr, Stefan,Fiege, Maren,Schmickler, Hans,Lex, Johann
, p. 3847 - 3854 (2007/10/03)
The diastereoselectivity of the photocycloaddition of benzaldehyde to furan was determined (exo/ endo = 212:1) and compared with the reaction of other carbonyl compounds and carbonyl analogues. These results were compared with Paterno-Buechi reactions of cycloalkenes and cyclic enol ethers. An increase in steric demand of the α-substituent in benzoyl compounds led to a change in exo/ endo-selectivity for furan cycloadditions that was not observed for cycloalkenes or cyclic enol ethers. Different ISC-reactive conformers with enhanced spin-orbit coupling are postulated as a reasonable explanation for the stereoselectivities observed. Additionally, solvent effects were studied, demonstrating the influence of photoinduced electron-transfer steps on the regio- and diastereoselectivity of Paterno-Buechi reactions with 2,3-dihydrofuran in polar solvents. Two bicyclic oxetanes (8 and 10) were characterized by X-ray structure analysis.
Regio- and Stereoselective Photocycloaddition Reactions of Aromatic Aldehydes to Furan and 2,3-Dihydrofuran
Griesbeck, Axel G.,Stadtmueller, Stefan
, p. 357 - 362 (2007/10/02)
The Paterno-Buechi reaction between benzaldehyde (1a), tolualdehyde (1b), mesitylaldehyde (1c), and 2,4-di-tert-butyl-4-methylbenzaldehyde (1d) and the electron-rich alkenes furan and 2,3-dihydrofuran has been investigated.The reaction with furan leads exclusively to exo-6-aryl-2,7-dioxabicyclohept-3-enes 2a to 2d in yields of 78percent to 97percent (2a, 2b).In the photoreaction of 2a and 2b with 2,3-dihydrofuran, however, mixtures of exo- and endo-7-aryl-2,6-dioxabicycloheptanes 3a and 4a (7:1) as well as 3b and 4b (15:1) could be isolated.The sterically more hindered aldehydes 1c and 1d give rise to exclusive formation of the endo adducts 3c and 3d.Irradiation of 1d in the presence of 2,3-dihydrofuran leads to the benzocyclobutenol 5 (Norrish-type II; up to 45percent) as a side product.The regioselectivity observed in these reactions may be explained by comparing the stability of the possible 1,4-diradical intermediates.The observed stereoselectivity could be rationalized by the geometry of the triplet 1,4-diradicals during the ISC process and by the life times of the resulting singlet 1,4-diradicals.
