A photoadduct of p-benzoquinones and diphenylacetylene

Photochemical Reactions of Chloranil with Cyclooctene, 1,5‐Cyclooctadiene, and Cyclohexene Revisited

“…On the basis of the melting point, this compound had been obtained in 42 % yield earlier. [16] There was no indication for both 11a and the spirooxetane 4. The isolation of the latter in 51 % yield had been claimed in 1964.…”

“…Finally, we employed conditions that approached those described by Bryce-Smith and Gilbert [16] as close as possible to us (Entry 7 of Table 1). Instead of a Hanovia S-500 medium-pressure mercury lamp, we utilised a 150 W lamp of the same kind.…”

“…Figure 1. Structures of the products described in the literature [5,16,17] to be formed from excited chloranil ( 3 CA) with cis-cyclooctene (cis-CO), cis,cis-1,5-cyclooctadiene (COD), and cyclohexene (CH).…”

“…Bryce-Smith and Gilbert [16] reported the formation of the spirooxetane 4 and the 1:2 cycloadduct 5, having two cyclobutane subunits, on irradiation of CA in benzene in the presence of cis-CO. They also noted that "1,5-cyclooctadiene shows closely parallel behaviour to that of cyclooctene".…”

“…After all, the corresponding 1:1 cycloadduct 1 was observed in addition to the 1:2 cycloadduct 2 in the case of CP (Scheme 1). However, Xu et al [5] did not mention a respective compound derived from CH, and Bryce-Smith and Gilbert [16] explicitely excluded such a compound derived from cis-CO.…”