1713-42-4Relevant articles and documents
Base-catalysed Ring Opening of 1,2-Diphenylcyclobutanols
Forward, Philip,Hunter, William N.,Leonard, Gordon A.,Palou, Josefina,Walmsley, David,Watt, C. Ian F.
, p. 931 - 935 (2007/10/02)
Cis- and trans-1,2-diphenylcyclobutanol have been prepared by literature methods and structural assignment confirmed by an X-ray crystal structure determination of the cis isomer.In the crystal structure, the four-membered ring has a pucker angle of 29 deg and the hydroxy group is pseudoequatorial with respect to the puckered ring.In aqueous base, both isomers rearrange to 1,4-diphenylbutan-1-one.Rates of this reaction in buffered aqueous dioxane have been measured.The isomers are almost equally reactive, kcis/ktrans ca. 0.7 at 25 deg C, although empirical force field calculations suggest that the cis isomer is more strained by 3.5 kcal mol-1.The solvent isotope effect, kH2O/kD2O is 0.68, and discrimination isotope effect (kH/kD) in protonation of the benzylic site of the product is 0.99 +/- 0.05.These ring openings are compared with those of the related cyclopropanols and with the corresponding reaction in a close acyclic analogue.
