The Chemical Behavior of 3,4‐Benzocycloocten‐1,5‐diyne

Abstract

The title compound 3,4‐benzocycloocten‐1,5‐diyne (1) is a highly reactive hydrocarbon that has been shown to undergo addition reactions with tetraphenyl‐cyclopentadienone(tetracyclone) to the 2:1 adduct 6, with octacarbonyldicobalt to the bis metal complex 7, with lithium aluminium hydride to the bis diene 9, and with various electrophilic reagents. In these latter cases cationic intermediates are generated from 1 and a transannular cyclization takes place leading to novel derivatives of 1,2‐dihydropentalene (31, 32, 35, 36, 43, 44).

The Preparation and Structures of Several Cross‐Conjugated Allenes (“Allenic Dendralenes”)

“…After drying (sodium sulfate), the solvent was removed by rotary evaporation, and the remaining oil was distilled; at 86°C/30 Torr the ester 15 was obtained as a colorless liquid (4.41 g, 58 %). 1 …”

“…However, a small sample could be separated by preparative GC (6 m OPN, 60°C), allowing the spectroscopic data to be recorded. 1 …”

“…After drying (sodium sulfate), the bis(ether) was purified by vacuum distillation at 98°C/0.1 Torr to afford 35 (106.6 g, 85 %) as a colorless oil. 1 …”

“…The bis(allene) 4 was isolated as a colorless oil (92 mg, 88 %), which rapidly polymerized to form a solid. 1 + , 103 (100), 78 (48), 77 (27), 65 (12), 40 (14), 29 (11). Because of the strong tendency of the hydrocarbon to polymerize, no satisfactory elemental analysis could be obtained.…”

“…3 mL, and the product was separated by preparative gas chromatography (10 m squalane column, 110°C) to afford 60 (60 mg, 60 %); colorless liquid. 1 4-(Trimethylsilylmethyl)hept-3-ene-1,6-diyne (59): A solution of 55 (1.04 g, 10.0 mmol) under N 2 in anhydrous diethyl ether (20 mL) was cooled to -78°C in a three-necked flask (100 mL). nButyllithium solution (20 mL, 1 n in hexane) was added, and the temperature was raised to -20°C.…”