1988 Fiscal Year Final Research Report Summary
Stereochemistry of 1,2-Asymmetric Rearrangements in Chiral Sulfinyl- cyclopropanes and Its Application to Asymmetric Synthesis
| Project/Area Number |
62570950
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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 |
Chemical pharmacy
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| Research Institution | Tohoku College of Pharmacy |
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Principal Investigator |
PROF.HIROI Kunio Tohoku College of Pharmacy, 薬学部, 教授 (00012641)
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| Co-Investigator(Kenkyū-buntansha) |
MATSUYAMA Nobuhiko Tohoku College of Pharmacy, 薬学部, 助手 (30173925)
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| Project Period (FY) |
1987 – 1988
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| Keywords | asymmetric synthesis / asymmetric quaternary carbon / 1,2-asymmetric rearrangement / thermal reaction / chiral sulfur atom / cyclopropane / シクロプロパン / シクロブタン |
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| Research Abstract |
This project has provided the first example of asymmetric induction in thermal rearrangements of cyclopropane systems affected by the chirality of optically ective sulfoxides.
Upon heating in refluxing benzene in the presence of p-toluenesulfonic acid, (Ss)-l-(l-hydroxy-l-phenethyl)-l-p-toluenesulfinylcyclopropane (1) underwent 1,2-rearrangement to give (Ss,4R)-4-methyl-4-phenyl-p-toluenesulfinylcyclobutene (2) with high stereospecificity. Reduction of the sulfoxide followed by hydrolysis of the enol thioether produced (r)-(-)-2-methyl-2-phenylcyclobutanone (3) with high enantiomeric excess. Treatment (Ss,1R)-1 or (Ss,1S)-1 with tosyl chloride in pyridine at 0 c gave (Ss,4R)-2 or (Ss,4S)-2 with high stereospecificity.
Mesylation of (R) - or (S)-1-(1-hydroxy-1-phenethyl)-1-p-toluenesulfenylcyclo-propane (4) with mesyl chloride -triethylamine at 0 c produced (R)- or (S)-4-methyl-4-phenyl-1-p-toluenesucenylcyclobutene (5) with retention of configuration and high enantiomeric excess, respectively.
The easy eccess to starting chiral chiral sulfoxides and the high degree of asymmetric induction in this rearrangement represent a potentially great advantage for the construction of asymmetric quaternary carbons. Furthermore, this method provides a facile entry to chiral cyclobutane derivatives, which have usually been hard to access.
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Research Products
(2 results)
