Stereoselective syntheses of (E)- and (Z)-1-arylalk-3-en-1-ynes and (E,E)-, (Z,E)-, (E,Z)-, and (Z,Z)-alka-1,5-dien-3-ynes via a one-pot multicomponent coupling reaction

Both 1-arylalk-3-en-1-ynes and alka-1,5-dien-3-ynes have been synthesized under extremely mild reaction conditions in Good to high yields via a sequential Suzuki-type and Sonogashira reaction in a one-pot manner. Thus, the protocol involves Cu-mediated cross-coupling reaction of (E)- or (Z)-alkenyldisiamylborane with (trimethylsilyl)ethynyl bromide in the presence of I M NaOMe and Pd/Cu-catalyzed cross-coupling reaction with aryl or alkenyl iodide in the presence of aqueous n-Bu4NOH. The reaction with aryl iodide is tolerant of a wide variety of functional groups on the aromatic ring and leads to the stereoselective formation of (E)- and (Z)-1-arylalk-3-en-1-ynes. In addition, the reactions with (E)- and (Z)-1-iodoalk-1-enes have accomplished the construction of all possible combinations of geometrical isomers, (E,E)-, (Z,E)-, (E,Z), and (Z,Z)-alka-1,5-dien-3-ynes.