C. Condeiu et al., THE DEOXYGENATION OF EPOXIDES WITH PHOSPHINES .2. THE FORMATION OF THE SYN-DIMER OF CYCLOBUTADIENE FROM FURAN, Revue Roumaine de Chimie, 39(7), 1994, pp. 855-857
In contrast to the known photochemical reaction of furan with tripheny
lphosphine (which leads to the anti-dimer of cyclobutadiene and triphe
nylphosphineoxide) the irradiation of a solution of furan and tri-n-bu
tylphosphine in acetone affords the syn-dimer of cyclobutadiene, toget
her with the corresponding phosphineoxide.