Oxy-sulfonylation of terminal alkynes via C–S coupling enabled by copper photoredox catalysis

Abstract

We report the first literature example using visible light-induced trimethylsilyl azide (TMSN3)-assisted copper-catalyzed oxy-sulfonylation of terminal C≡C bond to form β-keto sulfones (C-S bond formation). TMS-N3 promotes the reaction by...

Electrooxidative tricyclic 6–7–6 fused-system domino assembly to allocolchicines by a removable radical strategy

“…In addition, when the direct addition product 12 (for detailed information, see the ESI † ) was subjected to the standard electrochemical conditions, the cyclization product 3a was not obtained. Based on these experimental results and literature, 24 a radical mechanism is proposed for this electrooxidative radical reaction as depicted in Fig. 3b .…”

Visible‐Light‐Induced Oxidative α‐keto‐Dichlorination of Arylalkynes by CuCl2 at Room Temperature

“…(b) Visible light‐mediated synthesis of α,α‐dichloroketones [13,14] . (c) Visible light‐mediated CuCl2‐catalyzed oxidation internal alkynes to α‐diketones [17n] . (d) Current work: photooxidative dichlorination of alkynes through LMCT excitation of CuCl2.…”

“…To this end, our group has reported various green methods for a variety of C−C, C−N, C−S oxidative cross‐coupling, oxidation, and C−H annulation reactions [17] (which produce minimal amounts of chemical wastes) by using visible light (without any use of photosensitizers) and a simple, inexpensive, Earth‐abundant CuCl as a catalyst. Importantly, we reported the oxidation of aryl internal alkynes to form α‐diketones by photo‐irradiation of simple CuCl 2 (10 mol %) and O 2 in ACN, [17n] where photoexcited copper(II) superoxo oxidizes internal alkyne to diketones (Scheme 1c). In connection to this work, herein, we report the visible‐light‐induced oxidative α‐keto‐dichlorination of aryl alkynes to form α,α‐dichloroketones (DCAPs) or dichlorophenylacetophenones (DCPAPs) through ligand‐to‐metal charge transfer (LMCT) excitation of CuCl 2 .…”

Electrochemically Promoted Bifunctionalization of Alkynes for the Synthesis of β‐Keto Sulfones

“…[18,19] Moreover, alkynes were successfully applied to the synthesis of β-keto sulfones by metal catalysis or photocatalysis (Scheme 1e). [20][21][22][23][24] A manganese (III)-mediated and -catalyzed synthesis of β-keto sulfones via arylpropiolic acids with sodium sulfonates was developed using Mn(OAc) 3 (Scheme 1f). [25] In addition, β-keto sulfones were also synthesized by a copper(I)-catalyzed multicomponent reaction of aryldiazonium tetrafluoroborates, 3-arylpropiolic acids, sulfur dioxide and water at 0 °C.…”

“…β ‐Keto sulfones were also prepared from sodium sulfinates and oxime acetates using a recyclable heterogeneous copper catalyst at 100 °C (Scheme 1d) [18,19] . Moreover, alkynes were successfully applied to the synthesis of β ‐keto sulfones by metal catalysis or photocatalysis (Scheme 1e) [20–24] . A manganese (III)‐mediated and ‐catalyzed synthesis of β ‐keto sulfones via arylpropiolic acids with sodium sulfonates was developed using Mn(OAc) 3 (Scheme 1f) [25] .…”