Synthesis of a diquinocyclobutene

Synthesis and reactions of a tetraquinocyclobutane

“…Ether was added and the solution was washed with water several times, dried (MgS04), filtered, and evaporated. Recrystallization from hexane-ether gave sparkling irridescent purple crystals: NMR (CgDg) 6 1.26 (36 ), 1.28 (18 ), 1.63 (18 H), 6.92 (8 H), 7.25 (1 ), 8.07 (1 H); ir (CHCls) 3618 (w), 1582 cm-1 (vs); uv-visible Xmax (CHCI3) 300 nm (log e 4.11), 335 (4.33), 563 sh (4.76), 587 (4.82).…”

“…Compound 7 also reacts with alcohols to form "asymmetric adducts in which alcohol molecules seem to have reacted at one of the double bonds of the molecule". 8 Deprotonation of 4 to Its Dianion. Spectrophotometric titrations with various bases were attempted in order to convert 4 to its dianion.…”

A Hexapentaene‐Extended Quinocumulene Cyclotrimerized to a Tricyclobutabenzene Derivative

“…These results support the assignments. It was already known that oxidation of 2,6‐di‐ tert ‐butyl‐4‐phenylethynylphenol ( 14 ) with appropriate oxidizing agents led to the formation of the bismethylenecyclobutene 15 in good yield (Scheme ) 8. A radical species 16 (Scheme ) is postulated as a reactive intermediate of the reaction.…”