Pd-Catalyzed Domino Synthesis of Internal Alkynes Using Triarylbismuths as Multicoupling Organometallic Nucleophiles

Abstract

The domino coupling reaction of 1,1-dibromo-1-alkenes with triarylbismuth nucleophiles has been demonstrated to furnish disubstituted alkynes directly under catalytic palladium conditions. The couplings of triarylbismuths as multicoupling nucleophiles with 3 equiv of 1,1-dibromo-1-alkenes are very fast, affording high yields of alkynes in a short reaction time. Thus, an efficient domino process has been accomplished using 1,1-dibromo-1-alkenes as surrogates for internal alkyne synthesis in couplings with triarylbismuths in a one-pot operation.

Copper‐ and Phosphane‐Free Sonogashira Coupling of Arenediazonium o‐Benzenedisulfonimides

“…153–154 °C). NMR spectroscopic data were identical to those reported in the literature 24. MS (EI): m / z = 278 [M] + .…”

“…1,4‐Bis(2‐phenylethynyl)benzene (4l): White solid (0.45 g, 80 %), m.p. 183–184 °C (EtOH; ref 24. 153–154 °C).…”

Regioselective Synthesis of 2- and 3-Substituted Imidazo[1,2-a]pyridines

“…gem-Dibromovinyl substrates were prepared according to the literature procedures. [25][26][27] Solvents were dried over CaH 2 (DMF or DMSO), and freshly distilled prior to use. Unless otherwise indicated, all syntheses and manipulations were carried out under N 2 atmosphere.…”

Triphenylbismuthine

“…Triphenylbismuthine (or triarylbismuthines) also participate in threefold domino couplings with 1,1-dibromoalkenes (eq 19). 29 This reaction is useful for the synthesis of internal alkynes directly from 1,1-dibromoalkenes involving in situ elimination and coupling process. As 1,1dibromoalkenes are easily obtainable from the Ramirez olefination 30 or its modified Corey-Fuchs method, 31 this domino one-pot coupling method is useful for the preparation of internal alkynes directly from aldehydes through 1,1-dibromoalkenes.…”