Synthesis 2005(12): 1991-2007  
DOI: 10.1055/s-2005-869955
PAPER
© Georg Thieme Verlag Stuttgart · New York

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

Masayuki Hoshi*, Hidenori Nakayabu, Kazuya Shirakawa
Department of Applied and Environmental Chemistry, Kitami Institute of Technology, 165 Koen-cho, Kitami, Hokkaido 090-8507, Japan
Fax: +81(157)247719; e-Mail: hoshi-m@chem.kitami-it.ac.jp;
Further Information

Publication History

Received 13 January 2005
Publication Date:
20 June 2005 (online)

Abstract

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 1 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.

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A part of the results have been described previously. [11]

13

The amount of 1 M NaOMe could be reduced to three-quarters with about the same yield of product as the previous report: Hoshi, M.; Nakayabu, H.; Shirakawa, K. unpublished results.

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The work-up procedure should be carried out at or below room temperature in order to avoid any decomposition of the product.