1989 Fiscal Year Final Research Report Summary
Development of Highly Selective Asymmetric Reactions
| Project/Area Number |
63470012
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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 |
有機化学一般
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| Research Institution | The University of Tokyo |
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Principal Investigator |
NARASAKA Koichi FACULTY OF SCI. UNI. OF TOKYO, PROFESSOR, 理学部, 教授 (50016151)
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| Project Period (FY) |
1988 – 1989
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| Keywords | Asymmetric Catalyst / Chiral Titanium / Asymmetric Reaction / Diels- Alder Reaction / [2+2] Cycloaddition / Ene Reaction / Hydrocyanation / Kinetic Resolution |
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| Research Abstract |
As a chiral Lewis, titanium reagents have been prepared by introducing a 1,4-chiral diol moiety derived from dimethyl tartrate to titanium compounds. The chiral titanium reagents have found a wide application to various asymmetric reactions.
1. Acrylic acid and fumaric acid derivatives react with dienes to afford the [4+2] cycloadducts with high enantioselectivity by the combined use of a catalytic amount of the chiral titanium and Molecular Sieves 4A. Bicyclic carbocycles are synthesized in almost optically pure forms by intramolecular Diels-Alder reactions with the chiral titanium.
2. The chiral titanium reagent also promotes [2+21 cycloadditions between acrylic acid derivatives and ketene dithioacetals (or alkenyl or alkynyl sulfides). Cyclobutanes and cyclobutenes are prepared in high enantioselectivity.
3. Asymmetric intramolecular ene reaction is catalyzed with the chiral titanium, and cyclopentanone and cyclobexanones are obtained enantioselectively.
4. Various types of aldehydes react with cyanotrimethylsilane in the presence of the chiral titanium to give the corresponding cyanohydrins in more than 90%ee.
5. The chiral titanium alkoxide is efficiently employed in the kinetic resolution of racemic carboxylic acids derivatives as a chiral catalyst. alpha-Arylacetic acids are resolved in high selectivity.
6. Starting from the optically active intermediates thus prepared, C-analogue of oxetanocin, grandisol and epsilon-cadinene are synthesized in optically pure forms.
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