2002 Fiscal Year Final Research Report Summary
Stereoselective synthesis of terminal conjugated enynes using alkenylboron compounds
| Project/Area Number |
13650898
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
有機工業化学
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| Research Institution | Kitami Institute of Technology |
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Principal Investigator |
HOSHI Masayuki Kitami Institute of Technology, Engineering, Assoc. Prof., 工学部, 助教授 (00113712)
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| Project Period (FY) |
2001 – 2002
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| Keywords | alkenyldialkylborane / 2-bromo-1-(trimethylsilyl)acetylene / cross-coupling / copper(II) acetylacetonate / 3-alken-1-yne / 1-trimethylsilyl-3-alken-1-yne / Sonogashira reaction / 1-aryl-3-alken-1-yne |
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| Research Abstract |
We have studied the copper(II) acetylacetonate-catalyzed cross-coupling reaction of (E)- and (Z)-1-alkenyldialkylborane with 2-bromo-1-(trimethylsilyl)acetylene and the application of the cross-coupled products, (E)- and (Z)-3-alken-1-yne, to Sonogashira reaction. The results are as follows:
1. By using NaOMe (1M solution in methanol) as a base, the cross-coupling reaction as well as protodesilation proceeded simultaneously under very mild conditions, at -15 ℃ to room temperature, to provide (E)- and (Z)-3-alken-1-ynes in good yields with high regio- and stereoselectivities.
2. By using LiOH・H_2O as a base, the cross-coupling reaction proceeded with practically no protodesilation under the same conditions to afford (E)- and (Z)-l-trimethylsilyl-3-alken-1-ynes in moderate to good yields with high regio- and stereoselectivities.
3. Both (E)- and (Z)-3-alken-1-yne, in situ generated by the copper(II) acetylacetonate-catalyzed cross-coupling reaction, were subjected to the reaction with aryl iodide in a one-pot manner, and hence the reaction proceeded at room temperature in the presence of PdCl_2(PPh_3)_4-CuI as catalyst and tetrabutylammonium hydroxide as base to give the corresponding arylated conjugated enynes in high yields with high regio- and stereoselectivities.
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