Butyl 2-ethynylphenyl

Bromobenzotellurophene is cleaved by n-BuLi forming butyl-2-ethynylphenyl telluride. ... 

A route to 2-ethynylphenyl alkyl telluriums is suggested by the observation that butyl lithium cleaves the tellurophene ring in 3-bromobenzo[/>]tellurophene at low temperature producing butyl 2-ethynylphenyl tellurium in good yield. Phenyl lithium did not cleave the tellurophene ring even at 20°3. 

Bromobenzotellurophene did not react with phenyl lithium. Butyl lithium in diethyl ether/hexane cleaved the tellurophene ring, even at — 50°, yielding butyl 2-ethynylphenyl tellurium2. 

Butyl lithium in hexane cleaved 3-bromobenzotellurophene, even at — 50°, forming butyl 2-ethynylphenyl tellurium3. 

Butyl 2-Ethynylphenyl Tellurium3 A solution of 0.5 g (1.6 mmol) of 3-bromobenzotellurophene in 30 ml of diethyl ether is cooled to — 50°, 1.95 mmol of butyl lithium in hexane are added, and, after 30 min, the mixture is hydrolyzed with wet diethyl ether and then with water. The organic phase is separated, dried with anhydrous calcium chloride, filtered, and evaporated. The oily residue is chromatographed on silica gel with petroleum ether as the mobile phase to give an oil (Rf = 0.5) yield 0.33 g (71%). 

Iwasawa has reported the gold(III)-catalyzed reaction of N-(o-ethynylphenyl)imi-nes with electron-rich alkenes to form polycyclic indole derivatives [26]. As an example, reaction of N-[l-(l-pentynyl)phenyl]imine 28 and tert-butyl vinyl ether with a catalytic amount of AuBrs in toluene at room temperature led to isolation of the polycyclic indole 29 in 80% yield as a mixture of diastereomers (Scheme 11.3). Conversion of 28 to 29 presumably occurs via initial intramolecular hydroamination to form the gold carbene containing azomethine ylide 30 that undergoes intermo-lecular [3 + 2] cydoaddition with tert-butyl vinyl ether to form the carbene complex 31. 1,2-Migration of the 7t-propyl group to the metal-bound carbon atom coupled with deauration then forms 29. This transformation is also catalyzed efficiently by PtCl2 [26]. 

Magnetic ordering of unpaired electrons through these p-conjugated systems could be faintly observed by the measurement of magnetic susceptibility. For example, the magnetization curve for poly[(3,5-di-/-butyl-4-hy-droxyphenyl)acetylene] (11) [20] almost coincided with the Brillouin curve of 5 = 1/2, while the curve for poly[p-ethynylphenyl)hydrogalvinoxyl] (12)... 

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See also in sourсe #XX -- [ , ]

See also in sourсe #XX -- [ , ]

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