Transition-metal-free one-pot synthesis of alkynyl selenides from terminal alkynes under aerobic and sustainable conditions

Abstract

Alkynyl selenides were synthesized by a straightforward one-pot and three-step methodology, without the need of diselenides as starting reagents, under an oxygen atmosphere and using PEG 200 as the solvent. This procedure involves the in situ generation of dialkyl diselenides through a K3PO4-assisted reaction of an alkyl selenocyanate obtained by a nucleophilic substitution reaction between KSeCN and alkyl halides. Successive reaction with terminal alkynes in the presence of t-BuOK affords the corresponding alkyl alkynyl selenide in moderate to good yields. Finally, this methodology allowed the synthesis of 2-alkylselanyl-substituted benzofuran and indole derivatives starting from convenient 2-substituted acetylenes.

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

“…The metal-catalyzed reactions of diorganyl diselenides 4 with terminal alkynes has become a versatile tool for the synthesis of selanyl alkynes. [203][204] These studies…”

“…[201][202] have focused on the use of Cu, [205][206][207] Fe, [208][209][210] Ag [211] and In-based [212] catalytic systems (Scheme 107). [203][204][205][206][207][208][209][210][211][212]…”

One-Pot Multicomponent Polymerization, Metal-, and Non-Metal-Catalyzed Synthesis of Organoselenium Compounds

“…Heredia et al synthesized alkynyl selenides in moderate to good yields under aerobic metal-free conditions from the reaction of KSeCN, alkyl halides, and terminal alkynes using PEG 200 as the solvent. In this reaction, dialkyl diselenides were formed in situ from the K 3 PO 4 -assisted reaction of alkyl halides and KSeCN with terminal alkynes in the presence of t -BuOK ( Scheme 26 ) [ 76 ].…”

A New Family of Vinyl Selenocyanates with the Amide Function Based on the Reaction of Potassium Selenocyanate with 3-Trimethylsilyl-2-Propynamides

“…Treatment of organic selenocyanates with bases and reducing agents such as LiEt 3 BH, DIBAL [27], NaBH 4 [28,29], KOH, K 3 PO 4 [30,31], and K 2 CO 3 [32] leads to the formation of dialkyl(diaryl)diselenides, which are in turn very important reagents for organoselenium chemistry [33]. The reduction of organic selenocyanates to selenolates with sodium borohydride followed by the reaction of the generated selenolates with vinyl halides [31] or with terminal acetylenes in the presence of t-BuOK [34] makes it possible to obtain a wide range of functionalized organyl vinyl selenides. Disubstituted selenides with different substituents at selenium were also obtained from arylselenocyanates by the direct substitution of the cyano group for a hydrocarbon fragment in the reaction with alcohols in the presence of tributylphosphine [35,36], as well as by the reaction of benzylselenocyanates with lithium acetylenides [37].…”