Hypervalent Iodine‐Mediated Selective Oxidative Functionalization of (Thio)chromones with Alkanes

Abstract

C-C bond formation is the most fundamental way for the chain propagation in organic molecules. This achievement through tandem oxidation of two different C-H bonds represents the state of the art in organic synthesis. Selective functionalization of the ubiquitous aliphatic C-H bonds offers an attractive option for this oxidative cross-coupling methodology. To develop such a methodology under mild and "metal-free" conditions remains challenging. Herein, we report hypervalent iodine-mediated selective oxidative functionalization of aliphatic C-H bonds of alkanes with chromones and (thio)chromones. A wide range of alkanes, both cyclic and acyclic, has been found to react selectively and predictably in good yields. The developed methodology is also the first report of a direct oxidative functionalization of the C-2 position of (thio)chromones with alkanes to access bioactive compounds.

Oxidative Heterocycle Formation Using Hypervalent Iodine(III) Reagents

“…The reaction was found to be very versatile and a range of heterocycles, such as pyridine, quinoxaline, phthalazine, quinazoline, pyrimidine, benzimidazole, purine, and pyridopyrazine, underwent CDC to provide the cross-coupled products in good to excellent yields. The authors have recently shown that (thio)chromones, an important heterocyclic motif, undergoes oxidative cross coupling with several cyclic and acyclic alkanes in a similar manner to provide the corresponding alkylated (thio) chromones 150 (Scheme 40 (2)) [106].…”

The synthesis and biological activity of novel anthracenone-pyranones and anthracenone-furans

“…DMEDA is N,N 0 -dimethylethylenediamine. Compounds 4,9,[13][14][15][16]23,[26][27][28][29][30][31][32][33][34][35][36][37][38][39][40][41] have been prepared and characterised previously. 21 Non-1-yn-3-one (10) was prepared according to the procedure by Braddock et al 52 3.1.1.…”

“…21 Interestingly, a recent report on a non-metal mediated synthetic ring forming processes on simple chromones has come to light 22 along with the oxidative alkylation of these ring systems. 23 The varying biological activity of the pluramycin class of compounds, with different substitution at C2, reflects the importance of this region of the molecule. As part of furthering our investigations into this class of compounds we were interested in developing efficient syntheses of the anthracenone ring system with varying D-rings, as well as investigating the role which this ring system plays in the biological activity.…”

Metal‐Free Oxidative CC Bond Formation through CH Bond Functionalization

“…The mechanism of the reaction is similar to that of the corresponding aldehyde coupling (Scheme ). This methodology was later extended to include electron‐neutral substrates, such as chromones and thiochromones 48b…”