Cu/Pd‐Catalyzed Cascade Reactions of Cyclic Diaryliodoniums and Alkynes – Access to Fluorenes with Conjugate Enynes/Dienes

Abstract

Unlike the widely studied linear diaryliodoniums as electrophilic arylating reagents, cyclic diaryliodoniums have the potential to initiate dual arylations with atom and step economy. In our current work, cascade reactions of cyclic diaryliodoniums and two equivalent alkynes have been successfully achieved under mild conditions, catalyzed by CuI/PdCl2(PPh3)2. The transformation could also be realized in a stepwise way with two different alkynes or with one alkyne and one alkene. The reaction enables a rapid access to a variety of complex fluorenes containing conjugate enyne and diene fragments.

Heterocyclic Iodoniums for the Assembly of Oxygen-Bridged Polycyclic Heteroarenes with Water as the Oxygen Source

“…CDPIs can react with various nucleophiles including reactive carbon, nitrogen, and sulfur, leading to the formation of polycyclic frameworks (Scheme ). These obtained polycycles are often heavily hydrocarbon-oriented and lipophilic . In the drug discovery field, heterocyclic frameworks with a considerable number of heteroatoms are in demand to gain the druggability of pharmacologically active compounds .…”

Cyclic diaryliodonium salts: applications and overview

“…In their earlier study, Liu et al 56 found that cyclic diaryliodonium salt 4 and p -tolyl acetylene 9 could be used to produce 4-fold fluorenes 10 , which were previously developed accidentally. The authors attempted their previous investigation with the objective of finding an alternative to aliphatic diaryliodonium's inefficient mechanism and unwanted iodoarene side product.…”

Hypervalent organoiodine compounds: from reagents to valuable building blocks in synthesis

“…This strategy has been then extended to the preparation of alkyne-substituted alkylidenefluorenes 53 by replacing the arylboronic acid with a second equivalent of the terminal alkyne and performing the reaction at 35 °C ( Scheme 18 ) [ 58 ].…”