Base-Promoted Reactions of Organostibines with Alkynes and Organic Halides to Give Chalcogenated (Z)-Olefins and Ethers

Abstract

Herein, with air-stable chalcogenated stibines (Sb−ER) as organometallic chalcogenating reagents, we developed base-promoted (Z)-hydrochalcogenation of alkynes with DMSO/DMSO-d 6 as hydrogen/deuterium sources, giving chalcogenated (Z)-olefins in good yields and with excellent regioselectivity. These reagents, easily synthesized from halostibines with in situ generated [Zn(ER) 2 ] at room temperature within a few minutes, could be also used in the base-promoted C(sp 3 )−S(Se) crosscoupling with C(sp 3 )−X and copper-catalyzed C(sp 2 )−S(Se) cross-coupling with C(sp 2 )−X (X = F, CI, Br, I) under mild conditions. This protocol could also be simply extended to organobismuth complexes (Bi−ER) with good functional tolerance.

Nickel-free cross-electrophile coupling of unactivated alkyl bromides with thiosulfonates and sulfinyl sulfones

“…Strong interactions between Zn and thiosulfonates were observed according to following experiments. First, mixing Zn powder with thiosulfonate (2a) at low temperature (0 °C) afforded the corresponding thiol (22) and disulfide (23) in 10% and 86% 1 H NMR yield, respectively (Scheme 8A). Higher yield of thiol (22) was obtained when the reaction was conducted at 80 °C.…”

“…First, mixing Zn powder with thiosulfonate (2a) at low temperature (0 °C) afforded the corresponding thiol (22) and disulfide (23) in 10% and 86% 1 H NMR yield, respectively (Scheme 8A). Higher yield of thiol (22) was obtained when the reaction was conducted at 80 °C. Meanwhile, disulfide (23) was formed in much lower yield.…”

Pd-catalyzed site-selective C(sp2)–H chalcogenation of amino acids and peptides using a picolinamide auxiliary

“…[70][71][72][73][74][75] Therefore, the synthesis of chalcogenides has been an immense subject of study. In this regard, several metal-mediated traditional cross-coupling strategies [76][77][78][79][80][81][82][83] and metal-free protocols [84][85][86][87][88][89] have used typical approaches to assemble chalcogenides. However, most of the methods suffer from the inevitable need to perform pre-functionalization of the starting materials, limited substrate scope and harsh reaction conditions.…”

Trivalent Organostibines: Sb,N Ligands in Double N-Arylation of Primary Amines toward Functionalized Carbazoles

“…Recently, we obtained organostibines containing 5,6,7,12-tetrahydrodibenzo­[ c , f ]­[1,5]­azastibocines by nickel-catalyzed cross-coupling of halostibines with organoboronic acids . Due to the intramolecular interaction of Sb with N and the special N–Sb coordination bond, the synthesized organostibines mentioned above are not only excellent coupling partners with enhanced reactivity in transition-metal-catalyzed cross-coupling reactions , but also synthons in base-promoted synthesis of chalcogenated ( Z )-olefins and ethers (Scheme a) . We hypothesized that when 5,6,7,12-tetrahydrodibenzo­[ c , f ]­[1,5]­azastibocine-involved organostibines were used as ligands in Pd-catalyzed double N-arylation, the Sb could act as a donor (toward the Pd center) and an acceptor (toward the N atom) simultaneously.…”