Chemoselective and stereospecific iodination of alkynes using sulfonium iodate(i) salt

Abstract

An efficient and highly chemoselective iodination of alkynes using a sulfonium iodate(i) electrophilc reagent under metal-free conditions has been realized. The reactivity of sulfonium iodate(i) salt could be significantly diverse in the presence of water as the solvent, enabling the (E)-1,2-diiodoalkenes stereospecifically. This stereodivergent approach is amenable to a wide range of alkyne substrates and demonstrates a diverse functional group tolerance resulting in synthetically valuable 1-iodoalkyne and (E)-vicinal-diiodoalkenes in good to excellent yields (up to 99%) with 100% selectivity under ambient conditions.

On-DNA Alkyne Iodination and Acetylenic Coupling as a Useful Tool for DEL Synthesis

“…1-Haloalkynes are an important subclass of valuable precursors for a vast array of fascinating chemical processes . Among these, 1-haloalkynes were utilized in the Cadiot-Chodkiewicz reaction, Nozaki-Takai reaction, and Click reaction .…”

Sodiump-Toluenesulfinate/KI-Mediated Aerobic Oxidative Iodination of Terminal Alkynes for Synthesis of 1-Iodoalkynes and 1,3-Diynes

“…89～91 ℃ (lit. [9] 90～ 92 ℃); 1 H NMR (400 MHz, CDCl 3 ) δ: 7.35 (d,J＝8.5 Hz,2H),7.31 (d,J＝8.5 Hz,2H), 1.29 (s, 9H); 13 C NMR (100 MHz, CDCl 3 ) δ: 152. 14, 131.93, 125.28, 120.45, 94.30, 34.85, 31.20, 5.15 132.32, 127.42, 126.60, 126.46, 126.38, 120.73, 94.29, 34.09, 23.77, 4.…”

“…As classical iodinating reagents, molecular iodine can react with terminal alkynes with the assistance of Ag(I) salts, [4a] Cu(I) salts [4b] and bases [4c-4f] to access the corresponding 1-iodoalkynes (Scheme 1, path a). Indeed, taking the advantages of high reactivity, mild conditions and excellent selectivity, hypervalent iodonium saltssuch as PhI(OAc) 2 , [5] N-iodosuccinimide, [6] bis(sym-collidine)iodine(I) hexafluorophosphate, [7] HMBMIBDCI (an ionic liquid iodinating reagent) [8] and Me 3 SI(OAc) 2 , [9] as iodinating reagents and oxidants, can also be used for the direct oxidative iodination of terminal alkynes (path b). To develop economic and environmentally benign oxidative reactions, the use of iodide salts like KI, NaI, ZnI 2 and (n-Bu) 4 NI as iodosources is highly attractive, owing to the low cost and low toxicity of these compounds.…”

(E)-Di-iodination of Alkynes Using Dried Dowex H+/NaI Approach

“…However, if elevated temperatures are need, I 2 may not be practical because it sublimes so readily. Common methods for di-iodination reported in the literature consist of the use of hazardous and/or toxic compounds, such as oxidants, e.g., H 2 O 2 , iodine sources, e.g., trimethylsulfonium iodate and iodine monochloride, reagents like tetrafluoroboric acid and solvents, e.g., dichloromethane, dioxane, or tetrahydrofuran . Some procedures also use heavy-metal catalysts, like copper or cobalt …”