2001 Fiscal Year Final Research Report Summary
Development of the practical organic reactions based on the π-coordination of alkyne to Lewis acid
| Project/Area Number |
12554028
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (B)
|
| Allocation Type | Single-year Grants |
|---|
| Section | 展開研究 |
|---|
| Research Field |
物質変換
|
|---|
| Research Institution | Tohoku University |
|---|
Principal Investigator |
YAMAMOTO Yoshinori Tohoku University, Graduate School of Science, Professor, 大学院・理学研究科, 教授 (60029519)
|
|---|
| Project Period (FY) |
2000 – 2001
|
| Keywords | Lewis acid / Chelation / Alkynes / Chemoselectivity / π-Coordination / Epoxides |
|---|
| Research Abstract |
Lewis acid mediated chelatipn control is one of the most fundamental and efficient methodologies for effecting the selective carbon-carbon bond formation in modern organic synthesis. It is well accepted that the chelation-controlled feactions proceed through the coordination of a lone pair of heteroatoms, such as an oxygen of an aldehyde br a nitrogen atom of an imine, to a Lewis acid, which is recognized as a σ-σtype chelation. On the contrary, we found that chemo- and regioselective reactions of certain alkynyl and alkenyl aldehydes were accomplished through a σ-π chelation between a lone pair of the carbonyl compounds and π-electrons of the C-C multiple bond. We also found that the chemoselective ring opening of alkynyl epoxides in the co-existence of the corresponding alkyl epoxides is achieved in a Me_3Al mediated reaction with alkynyl lithium reagents; this interesting chemoselectivity is most probably a reflection of bidentate complexation to an n-electron pair of the oxygen atom of the epoxide and π-electrons of the C-C triple bond.
|
