1-アリール-1-ベンゾチオフェニウム塩の合成と反応
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概要
- 論文の詳細を見る
Reaction of [ο- (arylthio) phenyl] ethenes with bromine or ICl undergoes intramolecular cyclization to give 1-aryl-1-benzothiophenium salts. Electrophilic addition of [ο- (phenylthio) phenyl] alkynes with electrophiles such as HClO<SUB>4</SUB>, HBF<SUB>4</SUB>, Br<SUB>2</SUB>, and PhSCl also affords 1-phenyl-1-benzothiophenium salts. Copper-catalyzed reaction of 1-benzothiophenes with diphenyliodonium triflate gives 1-phenyl-1-benzothiophenium triflates directly. This method is especially effective for the synthesis of parent 1-phenyl-1-benzothiophenium salt. Reaction of 1-phenyl-1-benzothiophenium salts with halide ions leads to the formation of 1-benzothiophenes and (<I>Z</I>) -haloethenes, while the reaction with alkoxide ions provides only (<I>Z</I>) -alkoxyethenes. In the cases of 2-alkyl-subsituted and 3-unsubstituted benzothiophenium salts, allenes and alkynes are formed, respectively. Cycloaddition of 1-phenyl-1-benzothiophenium salts with cyclopentadiene or 1, 3-diphenylisobenzofuran proceeds efficiently in the cases of less substituted 1-phenyl-1-benzothiophenium salts. Phenyl migration is observed in the thermolysis of 1-phenyl-1-benzothiiophenium triflates, while the phenyl migration competes with the dephenylation in the photolysis. The reactions observed in this study are attributed to the loss of aromaticity of the thiophene ring.
- 社団法人 有機合成化学協会の論文
- 2002-03-01