Cyclic Hypervalent Iodine Reagents for Azidation: Safer Reagents and Photoredox-Catalyzed Ring Expansion

Abstract

Azides are building blocks of increasing importance in synthetic chemistry, chemical biology, and materials science. Azidobenziodoxolone (ABX, Zhdankin reagent) is a valuable azide source, but its safety profile has not been thoroughly established. Herein, we report a safety study of ABX, which shows its hazardous nature. We introduce two derivatives, tBu-ABX and ABZ (azidobenziodazolone), with a better safety profile, and use them in established photoredox- and metal-mediated azidations, and in a new ring-expansion of silylated cyclobutanols to give azidated cyclopentanones.

Ethynylbenziodazolones (EBZ) as Electrophilic Alkynylation Reagents for the Highly Enantioselective Copper‐Catalyzed Oxyalkynylation of Diazo Compounds

“…Therefore, we first selected tosyl-substituted benzamide 3a as the startingmaterial, which had been used previously for the synthesis of cyclic hypervalent iodine reagents. [11] In fact, the corresponding azidobenziodazolone had displayed enhanced stability compared with the benziodoxoloner eagent. The first EBZ reagent, TIPS-Ts-EBZ (2a), couldb eo btained in 96 %y ield on ag ram scale by using as lightly modified one-pot oxidation/alkynylation protocold evelopedb y Olofsson and co-workers.…”

Synthesis of α,ω‐Bis‐Enones by the Double Addition of Alkenyl Grignard Reagents to Diacid Weinreb Amides

“…Synthesized from benzo‐1,3‐dioxol‐5‐yl methyl ketone (4.6 g, 28.0 mmol) following the literature procedure for the synthesis of 1a in 52 % yield (3.29 g, 14.5 mmol) . The analytical data matched the previously published values . 1 H NMR (400.1 MHz, CDCl 3 ): δ = 5.67 (d, J = 2.0 Hz, 1H), 5.98 (d, J = 2.0 Hz, 1H), 5.99 (s, 2H), 6.77 (dd, J = 0.4, 8.2 Hz, 1H), 7.07 (dd, J = 0.4, 2.0 Hz, 1H), 7.11 (dd, J = 2.0, 8.2 Hz, 1H).…”

Recent Applications of the Zhdankin Reagent in Organic Synthesis

“…Despite the utility of the Zhdankin reagent, like many hypervalent iodine species, it is explosive and shock-sensitive, and injuries have been reported from its use. [25] In an attempt to mitigate these undesirable properties, Waser and coworkers have prepared two analogues of compound 3 with higher molecular weights (Fig. 2).…”