Iodo toluene

The relative reactivities of photodehalogenation of the three dibromobenzenes, the three bromotoluenes, the three bromoanisoles, the three bromophenols and the three iodo-toluenes in hexane have been determined by irradiation under otherwise identical conditions at X > 290 nm and at a > 230 nm377. With the short-wavelength radiation, the dibromobenzenes and the bromoanisoles react fastest, having almost equal reactivity. The bromotoluenes react about three times as slow and the iodotoluenes are somewhat less reactive than their bromo analogues. The bromophenols are very unreactive. At X > 290 nm, the highest yields are observed with the iodotoluenes, as expected on the basis of their absorption spectra. 

Pd(OAc)2 (47.35 % Pd) was purchased from Degussa. The compounds 4-iodo-toluene, n-butyllithium (1.6 M in hexane), 3-methyl-l-pentyn-3-ol, 2-butyne-l,4-diol, phenylacetylene, diphenylacetylene, 1-ethynyl-l-cyclohexanol and 2-methyl-... 

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