Chelations of Sulfur and Oxygen Atoms Assisted Cross-Coupling Reactions of Bisdithioacetals with Grignard Reagents in Nickel- Catalyzed Condition
碩士 === 國立臺灣大學 === 化學學系 === 84 === Aliphatic substituted dithioacetal cannot react with Grignard reagents under nickel-catalyzed conditions. However, they can couple with Grignard reagents in the presence of the the chel- ation effect of het...
| Main Authors: | , |
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| Other Authors: | |
| Format: | Others |
| Language: | zh-TW |
| Published: |
1996
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| Online Access: | http://ndltd.ncl.edu.tw/handle/69302411591976839588 |
| Summary: | 碩士 === 國立臺灣大學 === 化學學系 === 84 === Aliphatic substituted dithioacetal cannot react with Grignard
reagents under nickel-catalyzed conditions. However, they can
couple with Grignard reagents in the presence of the the chel-
ation effect of heteroatom in their chains or in the presence
of the allylic dithioacetals formation during the reaction.
Herein, we describe a new procedure to convert bisdithioacetals
to the corresponding homoallylic dithioacetals by reacting with
silylmethyl Grignard reagents. Hydoxy Groups will assist the
cross-coupling reactions between aliphatic dithioacetals and
Grignard reagents to yield olefin- ation products. Because of
the coordination of proximal O- and S- atom with nickel, the
otherwise unreactive aliphatic C-S bonds can be activated. The
competitive chelating ability bet- ween oxygen and sulfur in
these reaction is discussed.
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