Solvent effects in the fluorination of aromatic molecules with ‘F-TEDA-BF4’
摘要:
The type of functionalization of an aromatic molecule achieved with 1-chloromethyl-4-fluoro-1,4-diazobicyclo-(2,2,2)octane bis-tetrafluoroborate, 'F-TEDA-BF4', in trifluoroacetic acid depends on its structure: naphthalene and phenanthrene gave fluorinated products, anthracene gave the trifluoroacetate, while an addition process occurred with 9-methoxy-phenanthrene in methanol, and an addition-elimination process in trifluoroacetic acid.
The photolysis of 10,10-difluorophenanthren-9(10H)-one 1 in different solvents shows that the major competing reaction of the diradical formed by α-cleavage: recombination and hydrogen atom abstraction depends on the hydrogen atom donating ability of the solvent. Photolysis of 1 in cyclohexane in the presence of air or oxygen leads mainly to α-cleavage while photoreduction with the formation of 10
halonaphthols with benzyl/allylbromides is described. Halonaphthols are used as carbon-nucleophiles in dearomatization to form three-dimensional cyclic enones with excellent chemoselectivity, in which etherification of phenolic hydroxyl group could be restrained well by using cesium carbonate as the base. A wide range of cyclic enones is directly prepared from various substituted benzyl/allylbromides and halonaphthols
描述了卤代萘酚与苄基/烯丙基溴的第一次分子间亲电脱芳构化。卤代萘酚作为碳亲核试剂在脱芳构化中形成具有优异化学选择性的三维环状烯酮,其中以碳酸铯为碱可以很好地抑制酚羟基的醚化。从各种取代的苄基/烯丙基溴和卤代萘酚直接制备出范围广泛的环状烯酮。机理研究表明直接的 S N 2 反应途径。
Solvent effects in the fluorination of aromatic molecules with ‘F-TEDA-BF4’
作者:Marko Zupan、Jernej Iskra、Stojan Stavber
DOI:10.1016/0022-1139(94)03146-q
日期:1995.1
The type of functionalization of an aromatic molecule achieved with 1-chloromethyl-4-fluoro-1,4-diazobicyclo-(2,2,2)octane bis-tetrafluoroborate, 'F-TEDA-BF4', in trifluoroacetic acid depends on its structure: naphthalene and phenanthrene gave fluorinated products, anthracene gave the trifluoroacetate, while an addition process occurred with 9-methoxy-phenanthrene in methanol, and an addition-elimination process in trifluoroacetic acid.