1989 Fiscal Year Final Research Report Summary
Development of New Radical Acceptors and Their Application to Organic Synthesis
| Project/Area Number |
63470077
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
Synthetic chemistry
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| Research Institution | Chiba University |
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Principal Investigator |
OGURA Katsuyuki Chiba University, Faculty of Engineering, Professor, 工学部, 教授 (60114253)
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| Project Period (FY) |
1988 – 1989
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| Keywords | Radical addition / Vinyl sulfone / Ketene dithioacetal S,S-dioxide / Captodative effect / MT-sulfone / Ketone synthesis |
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| Research Abstract |
The purpose of this project was to develop the alkenes having sulfur functionalities as new radical acceptors. Especially our attention was paid on ketene dithioacetal S,S-dioxides and vinyl sulfones, and the following results were attained.
1. Ketene dithioacetal S,S-dioxides were found to be an efficient acceptor of radicals. In particular, 1-Hydroxyalkyl radicals, and 1- alkoxyalkyl radicals added to the ketene dithioacetal S,S-dioxides with a high efficiency. In comparison with the corresponding vinyl sulfones, they exhibited higher ability to accept hexyl radical (4 times) or 2- hydroxy-2-propyl radical (2.4 times).
2. When ketene dithioacetal S,S-dioxides having a halogen atom at the omega- position was treated with tributyltin hydride in the presence of a radical initiator (AIBN) in refluxing benzene, an intramolecularly cyclized product was obtained. It is noteworthy that a highly strained cyclobutane derivative can be formed in ca. 50% yield. This is attributable to the stabilization of an intermediary cyclization radical by a combination of thio and sulfonyl groups (captodative effect).
3. On irradiation or heating of the alcoholic solution of a vinyl sulfone containing a catalytic amount of AIBN, a radical chain mechanism operates to give an adduct of 1-hydroxyalkyl radical in a high yield.
4. The adduct, which was derived from a ketene dithioacetal S,S-dioxide and a radical, was found to afford the corresponding ketone by alkylation with an alkyl halide and a base (NaH or butyllithium) followed by acidic hydrolysis.
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