| Project/Area Number |
14540497
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (C)
|
| Allocation Type | Single-year Grants |
|---|
| Section | 一般 |
|---|
| Research Field |
Organic chemistry
|
|---|
| Research Institution | HIROSHIMA UNIVERSITY |
|---|
Principal Investigator |
KOJIMA Satoshi Hiroshima University, Graduate School of Science, Associate Professor, 大学院・理学研究科, 助教授 (70215242)
|
|---|
| Project Period (FY) |
2002 – 2003
|
| Project Status |
Completed (Fiscal Year 2003)
|
| Budget Amount *help |
¥3,500,000 (Direct Cost: ¥3,500,000)
Fiscal Year 2003: ¥1,200,000 (Direct Cost: ¥1,200,000)
Fiscal Year 2002: ¥2,300,000 (Direct Cost: ¥2,300,000)
|
|---|
| Keywords | 8-phenylmenthol / pyridinium ylide / cyclopropanation reaction / 8-phenylmenthylamine / diastereoselectivity / substituent effect / chiral pyridine / 不斉 / フェニルアラニン |
|---|
| Research Abstract |
Examination of substituent effects in the diastereomeric cyclopropanation reaction of N-alkoxycarbonylmethyl pyridinium ylides bearing an 8-phenylmenthyl group as the chiral auxiliary was carried out. It was found that introduction of an electron donating 4-methoxy group gives rise to selectivities up to 964 for the reaction with a t-Bu substituted methylidene malononitrile substrate. Although selectivities up to 8317 could be observed for substrates bearing aromatic substituents, those for other substrates bearing aliphatic substituents did not exceed 7030. In order to raise the selectivity as a whole, we decided to examine 8-phenylmenthylamine in the place of 8-phenylmenthol as the chiral auxiliary. The amine could be prepared with selectivities up to 8911 and 97% yield. Examination of the diastereomeric cyclopropanation reaction on the t-Bu substituted methylidene malononitrile substrate resulted in selectivities up to 2 98, and as a whole the selectivity (63:37 to 12:88) was also higher than that in the ester series for other substrates. It was also found that the absolute stereochemistry for the major products of the amide series was opposite of that of the major product of the ester series. Modification of reaction conditions gave rise to bicyclic products bearing a cyclic imide moiety. Based upon the idea that introduction of chirality into the pyridine ring would allow for recycling of the chiral source, several chiral pyridines with chiral auxiliaries in the 3 position were examined. Unfortunately, however, no asymmetric induction could be observed. In an examination of the cyclopropanation reaction between a chloroketone and a conjugated olefin substrate, it was found that the reaction is catalyzed by 4-dimethylaminopyridine
|
