Synthesis of fluoro-functionalized diaryl-λ3-iodonium salts and their cytotoxicity against human lymphoma U937 cells

Recent Advances in the Synthesis and Medicinal Chemistry of SF5 and SF4Cl Compounds

This short review covers the most important advances published in the literature during the last five years, concerning the synthesis, chemical modifications, and applications of SF5 and SF4Cl compounds in medicinal/bioorganic chemistry and materials science.

1 Introduction

2 Methods for Incorporation/Manipulation of SF4Cl/SF5 Groups

2.1 Nonaromatic SF5 Compounds via Direct Pentafluorosulfanylation of Alkenes and Alkynes

2.2 SF4Cl- and SF5-Aryl/Heteroaryl Derivatives

3 Synthesis of SF5/SF4Cl/SF4-Substituted Small Molecules

3.1 Heterocycles

3.2 Amines and Amino Acids

3.3 α-SF5 ketones

3.4 Miscellaneous Alkyl-, Alkenyl-, and Aryl-SF5 Compounds

4 Medicinal/Biological Applications

4.1 Anticancer Compounds

4.2 Antibacterial and Antiparasitic Compounds

4.3 Central Nervous System

4.4 Miscellaneous Biological Activity

5 Materials Science Applications

6 Conclusion

Scalable electrochemical synthesis of diaryliodonium salts

Cyclic and acyclic diaryliodonium are synthesised by anodic oxidation of iodobiaryls and iodoarene/arene mixtures, respectively, in a simple undivided electrolysis cell in MeCN-HFIP-TfOH without any added electrolyte salts. This atom efficient process does not require chemical oxidants and generates no chemical waste. More than 30 cyclic and acyclic diaryliodonium salts with different substitution patterns were prepared in very good to excellent yields. The reaction was scaled-up to 10 mmol scale giving more than four grams of dibenzo[b,d]iodol-5-ium trifluoromethanesulfonate (>95%) in less than three hours. The solvent mixture of the large-scale experiment was recovered (>97%) and recycled several times without significant reduction in yield.

Studies of Halogen Bonding Induced by Pentafluorosulfanyl Aryl Iodides: A Potential Group of Halogen Bond Donors in a Rational Drug Design

The activation of halogen bonding by the substitution of the pentafluoro-λ⁶-sulfanyl (SF₅) group was studied using a series of SF₅-substituted iodobenzenes. The simulated electrostatic potential values of SF₅-substituted iodobenzenes, the ab initio molecular orbital calculations of intermolecular interactions of SF₅-substituted iodobenzenes with pyridine, and the ¹³C-NMR titration experiments of SF₅-substituted iodobenzenes in the presence of pyridine or tetra (n-butyl) ammonium chloride (TBAC) indicated the obvious activation of halogen bonding, although this was highly dependent on the position of SF₅-substitution on the benzene ring. It was found that 3,5-bis-SF₅-iodobenzene was the most effective halogen bond donor, followed by o-SF₅-substituted iodobenzene, while the m- and p-SF₅ substitutions did not activate the halogen bonding of iodobenzenes. The similar ortho-effect was also confirmed by studies using a series of nitro (NO₂)-substituted iodobenzenes. These observations are in good agreement with the corresponding Mulliken charge of iodine. The 2:1 halogen bonding complex of 3,5-bis-SF₅-iodobenzene and 1,4-diazabicyclo[2.2.2]octane (DABCO) was also confirmed. Since SF₅-containing compounds have emerged as promising novel pharmaceutical and agrochemical candidates, the 3,5-bis-SF₅-iodobenzene unit may be an attractive fragment of rational drug design capable of halogen bonding with biomolecules.