- Selective Preparation of Fluorene Derivatives Using the t-Butyl Function as a Positional Protective Group
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Several 4-substituted 2,7-di-t-butylfluorene derivatives (3) were prepared by electrophilic substitutions of 2,7-di-t-butylfluorene (1). 4-Substituted fluorene (4), such as 4-bromo- (4a), 4-methyl (4e), and 4-aacetylaminofluorene (4j), were obtained by the trans-t-butylations of 3.Although we attempted to synthesize 1,8-disubstituted fluorene from 3,6-di-t-butylfluorene (2) which was derived from 2,2'-diiodo-4,4'-di-t-butyldiphenylmethane (5), by the same methods, we obtained only 2,7-disubstituted fluorene derivatives (8); it turned out electrophilic substitutions of 2 gave 2,7-disubstituted 3,6-di-t-butylfluorene derivatives.
- Kajigaeshi, Shoji,Kadowaki, Toshiya,Nishida, Akiko,Fujisaki, Shizuo
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