1989 Fiscal Year Final Research Report Summary
Development and Application of Novel Ring-Expansion Reaction
| Project/Area Number |
63550621
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
有機工業化学
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| Research Institution | KYOTO UNIVERSITY |
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Principal Investigator |
TAKEUCHI Ken'ichi Kyoto Univ. Hydrocarbon Chemistry, Professor, 工学部, 教授 (50026358)
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| Co-Investigator(Kenkyū-buntansha) |
KINOSHITA Tomomi Kyoto Univ. Hydrocarbon Chemistry, Lecturerer, 工学部, 助手 (10026289)
KOMATSU Koichi Kyoto Univ. Hydrocarbon Chemistry, Associate Professor, 工学部, 助教授 (70026243)
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| Project Period (FY) |
1988 – 1989
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| Keywords | Bridgehead aldehyde / Benzoyl triflate / Ring-expansion reaction / 1,2-Diol / 4-Homoadamantanones / Keto cation / Solvolysis reaction / Carbocation intermediate |
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| Research Abstract |
1. Development of Nobel Ring-Expansion Reaction--Previously, we found a nobel ring-expansion of bridgehead aldehydes to 1,2-diol monobenzoates by use of benzoyl triflate. In this work, the method was applied to the bridgehead aldehydes of bicyclo [3.2.1] octyl, bicyclo[3.3.1] nonyl, and bicyclo[3.2.2] nonyl systems, and various new bicyclic 1,2-diols were successfully obtained. It was also demonstrated that the ring-expansion could be applied to the syntheses of bicyclic 1,2-diols labeled with ^2H or ^<13>C at the 2-position, 1-chlorobicyclo[2.2.2]octan-2-one, and various 3- alkyl(or aryl)-4-homoadamantanones.
2. Allylic Conjugation of 2-Methylene Bridgehead Carbocations--The logarithms of the rates of solvolysis of 2-methylene bridgehead compounds relative to the corresponding parent compounds were found to sigmoidally correlate with olefinic strain of the corresponding bridgehead olefins. The results, combined with our previous results on the rates of solvolysis of 2-oxo derivatives, showed that the delocalization of the positive charge of a 2-oxo carbocation to the carbonyl oxygen would be negligibly small. The methodology will be applied to the examination of the delocalization of positive charge to the imino or thiocarbonyl heteroatom.
3. Through-Bond Interaction in 3-Oxo Carbocations--The rates of solvolysis of 3-oxobicyclo[2.2.2]oct-l-yl derivatives were found 10^3 greater than expected from the inductive electron withdrawing effect of the carbonyl group. The rate and product studies demonstrated that the positive charge delocalizes to the carbonyl oxygen via through-bond interaction.
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