Synthesis of Heterocycle-Containing 9,9-Diarylfluorenes Using Superelectrophiles.
Makafui GasonooAkinari SumitaKenneth N BoblakKristen GiuffreTomohiko OhwadaDouglas A KlumppPublished in: The Journal of organic chemistry (2017)
A superacid-promoted method for the synthesis of 9,9-diarylfluorenes is described. The chemistry involves cyclizations and arylations with biphenyl-substituted heterocyclic ketones and a mechanism is proposed involving superelectrophilic intermediates. The key reactive intermediates-dicationic and trication fluorenyl cations have been observed by low-temperature NMR and the mechanism has been further studied using DFT calculations.