Functionalized fluorenes via dicationic electrophiles

Abstract

Dicationic fluorenyl cations are shown to react with nitriles to provide amide-functionalized fluorenes. A similar reaction with alcohols gives ether derivatives. The chemistry is initiated by the reactions of N-heterocyclic ketones in a superacidic solution. This leads to cyclizations involving 2-biphenyl groups and formation of the reactive fluorenyl cations.

Unexpected cytotoxicity of a triisopropylsilylated syringaldehyde derived cinnamic acid amide

“…The corresponding carbons were detected in the 13 C NMR spectrum at  = 147.1 and 117.1 ppm, respectively. The reaction of piperidine with 2-chloro-ethanol gave 4 [31][32][33][34] whose reaction with 3 afforded 5 as a colorless solid in 92% isolated yield. Desilylation of 5 with tetra-n-butylammonium fluoride trihydrate in THF yielded 6.…”

Superelectrophiles: Recent Advances

“…Mills and coworkers examined the first dicationic fluorenyl cations and noted their instability [ 26 , 27 , 28 ]. Our group developed an efficient route to 9,9-diarylfluorenes through a superacid-promoted cyclization ( Scheme 7 ) [ 29 , 30 ]. For example, the pyrazine derivative 24 undergoes reaction in superacid with benzene to give the 9,9-diarylfluorene product 28 in 91% yield.…”