Naslov
The stereoselectivity of the Paterno-Buechi reaction between tertiary 2-furylmethanol derivatives and aromatic carbonyl compounds : on the nature of the hydroxy directing effect

Autori
D'Auria, Maurizio ; Emanuele, Lucia ; Racioppi, Rocco.

Izvornik
Photochemical & photobiological sciences (1474-905X) 4 (2004), 10; 927-932

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
furan-derivatives; regioselectivity

Sažetak
The photochemical reaction of 1-(2-furyl)-1-phenylethanol with benzaldehyde gave a mixture of regioisomeric products. The adduct obtained on the more hindered side of the molecule was obtained with complete diastereoselectivity. The same substrate with benzophenone gave only one product with a diastereoisomeric excess of 48%. The reaction of 2-(2-furyl)- 3, 3-dimethylbutan-2-ol with benzaldehyde and benzophenone gave the corresponding adducts on the more hindered side of the molecule with diastereoisomeric excesses of 42 and 71%, respectively. These results, and also those obtained using 2-furylphenylmethanol with benzophenone and acetone ( complete diastereoselectivity and absence of diastereoselectivity, respectively), were explained assuming the attack of the excited carbonyl compound on the same side as the hydroxy group, through the formation of a hydrogen bond or of a complex. This type of attack gave the biradical intermediate in preferential conformations. The relative energies of these conformers account for the observed diastereoselectivity.

Izvorni jezik
Engleski

Znanstvena područja
Kemija

POVEZANOST RADA