Natural Deep Eutectic Solvent-Catalyzed Selenocyanation of Activated Alkynes via an Intermolecular H-Bonding Activation Process

Abstract

By employing cheap and biodegradable natural deep eutectic solvent as the catalyst and reaction media, the selective selenocyanation of activated alkynes via an intermolecular H-bonding activation pathway has been achieved, which allows for the efficient construction of various Z-vinyl selenolates.

Synthesis of Seleno‐Heterocycles via Electrophilic/Radical Cyclization of Alkyne Containing Heteroatoms

“…[197] Also, the selective selenocyanation of activated alkynes 325 via an intermolecular H-bonding activation pathway has been achieved by using glycolic acid. [198] Iodoselanylation of simple alkynes 328 was successfully achieved under mild conditions using commercially available molecular iodine (I 2 ) and diorganyl diselenides 4 as starting materials, this afforded the (E)-β-iodoalkenyl selenides 329 in good to excellent yields and with high regio-and stereoselectivity. [199] The copper-catalyzed addition of halide and sulfide/ selenide groups to internal alkyne 328 was carried out using disulfides/diselenides 4 with n-Bu 4 NX (X=Br, I or Cl) in air, selectively prepared the corresponding anti-configured haloalkenyl sulfide/selenide 330 (Scheme 105).…”

Direct cyanation, hydrocyanation, dicyanation and cyanofunctionalization of alkynes

“…Under ultrasonic radiation, treatment of alkynes 63 with H 2 O and KSeCN in natural deep eutectic solvent (ChCl/glycolic acid) afforded the corresponding Z-vinylselenolates 64 in 78-94% yields with Z/E ratio from 14 : 1 to 39 : 1. 45 The plausible mechanism for deep eutectic solvent catalysed selenocyanation of activated alkynes was depicted in Scheme 37. First, two hydrogen bonds formed between the oxygen atom of the carboxyl group in alkynes and the H atom of the hydroxyl groups (glycolic acid) in DES, resulting in enhanced polarization of carbonyl group of alkynes (N 0 ), which was in resonance with a zwitterionic intermediate O 0 .…”

“…Finally, the intermediate P 0 captured a proton (in situ generated by ultrasound-assisted selfionization of H 2 O) on the reverse side of the sterically hindered H-bond activated atom to produce the desired Z-vinyl selenocyanates with concomitant release of the DES to full the catalytic cycle. 45 A green selenocyanation of activated alkynes catalysed by lactic acid was achieved by He in 2019. Treatment of a mixture of alkynes 65, H 2 O, KSeCN and lactic acid at ambient temperature under ultrasonic conditions (30)(31)(32) in open air led to the expected Z-3-selenocyanatoacrylates and analogues 66 in excellent yields.…”

Deep Eutectic Solvent Mediated Alkyne‐Carbonyl Metathesis (ACM) Reaction for the Synthesis of 2H‐Chromene Derivatives

“…Besides, their important physicochemical properties, they have also influenced the molecule interactions with reaction substrate. Consequence of these interactions, they have been utilized in many fields such as (i) extraction of bioactive compounds from mixture (ii) bio‐catalytic reaction (iii) material chemistry, (iv) organic synthesis and (v) dissolution of metal oxides. In order to redress the problems associated with safety and environment issues arising from conventional volatile organic solvents, utility of DESs has been recognized by several synthetic groups around the world .…”