Reaction of diphenylcyclobutenedione with methyl phosphites

✍ Scribed by Paul R. Ortiz de Montellano; Patricia C. Thorstenson

• Publisher: Elsevier Science
• Year: 1972
• Tongue: French
• Weight: 169 KB
• Volume: 13
• Category: Article
• ISSN: 0040-4039
• DOI: 10.1016/s0040-4039(01)84439-7

✦ Synopsis

The reaction of phenylcyclobutenedione (I) with trimethylphosphite has recently been reported to give the adduct (II). (2) Not surprisingly products derived from the cyclobutadiene structure (III) were not observed, although such an intermediate would be analogous to the products obtained with simpler diketones. (3) The lack of reaction of diphenylcyclobutenedione (IV) with trimethylphosphite is noted in this same publication. O=i(OMe) 2 __ I II III In the course of investigating condensation reactions of cyclobutenediones we have studied the thermal and photolytic reactions of diphenylcyclobutenedione with trimethyl-and dimethylphosphite. In contrast to the earlier work, (2) we have observed addition reactions with both reagents. A solution of diphenylcyclobutenedione (IV) (4) in neat trimethylphosphite on standing three days at room temperature gave the adduct (V) in 91% yield. This same 1,2-adduct was obtained in 72% yield on heating the solution two hours at 8G0c. It was essential that the trimethylphosphite be freshly distilled from sodium, since impure material severely reduced the yield of No. 9 P(OMe13 hr B )* tOMel (XII)