Palladium-catalyzed cyclocarbonylation of cyclic diaryliodoniums: Synthesis of fluorenones

Cyclic diaryliodonium salts: applications and overview

Owing to the recent renewed interest and groundbreaking advances in hypervalent chemistry, cyclic diaryliodonium salts have had a myriad of unique applications in the past decade. Their numerous properties, such as an efficient dual arylation mechanism, straightforward one-pot synthesis compatibility, wide substrate scope, and functionalization tolerance, have made them appropriate starting materials for many bioactive compounds. Fluorenes, thiophenes, carbazoles, phenanthrenes, and many other useful cyclic bioactive molecules that are essential for pharmaceutical synthesis can be readily accessed from cyclic diaryliodonium salts. Particular focus has been given to the high optical activity and good enantiomeric excess of the products that facilitate the easy formation of many difficult-to-obtain optical isomers, such as atropisomers. This review aims to compile and summarize all the recent advances in synthesizing methodologies to prepare the important compounds where cyclic diaryliodonium salt is an integral part of the methodologies and would hopefully provide a good foundation for further research on this topic.

Metastable 9-Fluorenone: Blueshifted Fluorescence, Single-Crystal-to-Single-Crystal Reactivity, and Evaluation as a Multimodal Fingermark Visualization Treatment

A metastable form of 9-fluorenone (MS9F) has been characterized using Raman spectroscopy, fluorimetry, and X-ray diffraction techniques. MS9F emits blue fluorescence (λ_max =495 nm) upon 365 nm irradiation and undergoes a single-crystal-to-single-crystal (SCSC) transformation to reach the ground state form (GS9F) over approximately 30 minutes, whereupon it emits the expected green fluorescence. A structure-property relationship for this fluorescent behavior has been posited. MS9F and GS9F were applied as a means of visualizing latent fingermarks on a nonporous surface. This approach identified three different modes of fluorescent fingermark visualization using 9-fluorenone.

Synthesis of Dibenzofurans from Cyclic Diaryliodonium Triflates and Water via Oxygen-Iodine Exchange Approach

An efficient synthesis of a variety of dibenzofuran derivatives via Cu-catalyzed cyclization diaryliodonium salts in water is achieved. Various dibenzofuran derivatives could be obtained in good to excellent yields via this oxygen-iodine exchange approach. A concise synthesis of organic semiconducting material molecule has been achieved using this method.