Fluorene/fluorenone carboxamide derivatives as selective light-up fluorophores for c-myc G-quadruplex

6aH-Benzo[α]fluorene: NMR evidence of the unexpected product of the reaction of butyryl chloride with 1,2-diphenylacetylene

The reaction of butyryl chloride with ethynylbenzene in the presence of AlCl3 afforded a mixture of the Z/E-isomers of 1-chloro-2-phenylhex-1-en-3-one. 1,2-Diphenylethyne under these conditions gave a novel polycarbocycle core, 6aH-benzo[a]fluorene. The chemical structure of 11-chloro-5,6-diphenyl-6a-propyl-6aH-benzo[a]fluorene was established by means of IE-MS, 1 H, 13 C NMR, COSY, HSQC, HMBC, and 2D INADEQUATE technique.

Direct Benzylic C-H Functionalization with Fluorenones under Visible-Light Irradiation

An external photocatalyst-free benzylic C-H functionalization with fluorenones under visible-light irradiation has been achieved. This transformation provides an efficient synthetic approach to 9-benzylated fluorenols in ≤91% yield with 100% atom economy under mild conditions. Spectroscopic studies suggest that a reductive quenching of photoexcited fluorenones with toluene derivatives generates ketyl radicals and benzyl radicals, which undergo a cross-coupling to afford the desired fluorenols.

Recent Progress in Cyclic Aryliodonium Chemistry: Syntheses and Applications

Hypervalent aryliodoumiums are intensively investigated as arylating agents. They are excellent surrogates to aryl halides, and moreover they exhibit better reactivity, which allows the corresponding arylation reactions to be performed under mild conditions. In the past decades, acyclic aryliodoniums are widely explored as arylation agents. However, the unmet need for acyclic aryliodoniums is the improvement of their notoriously low reaction economy because the coproduced aryl iodides during the arylation are often wasted. Cyclic aryliodoniums have their intrinsic advantage in terms of reaction economy, and they have started to receive considerable attention due to their valuable synthetic applications to initiate cascade reactions, which can enable the construction of complex structures, including polycycles with potential pharmaceutical and functional properties. Here, we are summarizing the recent advances made in the research field of cyclic aryliodoniums, including the nascent design of aryliodonium species and their synthetic applications. First, the general preparation of typical diphenyl iodoniums is described, followed by the construction of heterocyclic iodoniums and monoaryl iodoniums. Then, the initiated arylations coupled with subsequent domino reactions are summarized to construct polycycles. Meanwhile, the advances in cyclic aryliodoniums for building biaryls including axial atropisomers are discussed in a systematic manner. Finally, a very recent advance of cyclic aryliodoniums employed as halogen-bonding organocatalysts is described.