Regio- and Stereoselective Hydroiodination of Internal Alkynes with Ex Situ-Generated HI

Abstract

Herein, we report an efficient and practical hydroiodination of internal alkynes using HI generated ex situ from the readily available triethylsilane and I2. This system offers high regio- and stereoselectivity to afford (E)-vinyl iodides in good yields under mild conditions. Furthermore, the hydroiodination reaction shows high functional group tolerance toward alkyl, methoxy, halogen, trifluoromethyl, cyano, ester, halomethyl, acid-sensitive silyl ether, and acetal moieties.

β-Boron Effect Enables Regioselective and Stereospecific Electrophilic Addition to Alkenes

“…Keeping in mind that the B(MIDA) moiety may decompose in strong aqueous hydroiodic acid and that gaseous HI is toxic and corrosive for direct handling, we resorted to a two-chamber reaction system by using HI generated ex situ from HSiEt 3 (3.0 equiv) and I 2 (3.0 equiv). 32 As expected, this method allowed for the successful transformations of a wide variety of functionalized allyl MIDA-boronates to the corresponding β-iodinated products (14− 24). As a proof of concept, regioselective hydrochlorination (25−28) and hydrobromination (29−35) were also realized by using (COCl) 2 33 and (COBr) 2 34 as H-X precursors, respectively, demonstrating the general applicability.…”

Recent Advances in the Functionalization of Terminal and Internal Alkynes

“…In 2021, Kondo and co‐workers reported hydroidonation of internal alkynes using ex situ generated HI from triethylsilane and I 2 (Scheme 43). [41] This methodology showed high functional group tolerance under mild reaction conditions, to afford ( E )‐vinyl iodides in good yields along with high regio‐ and stereoselectivity. The initial reaction was performed using 1,2‐diphenylethyne as the model substrate.…”

Visible-light-induced phosgenation of amines by chloroform oxygenation using chlorine dioxide

“…1, an H-shaped reaction glass tube (COware) was employed as the two-chamber system. 10 One side of the system (Chamber A, 5 mL) contained an aqueous ClO 2 ˙ solution prepared through the mixing of NaClO 2 with HCl. The other side of the system (Chamber B, 2 mL) contained a CHCl 3 solution with the substrate.…”