1995 Fiscal Year Final Research Report Summary
Development of Synthetic Radical Reactions of Cyclic Compounds based on Characteristics of Silicon.
| Project/Area Number |
06453135
|
|---|
| Research Category |
Grant-in-Aid for General Scientific Research (B)
|
| Allocation Type | Single-year Grants |
|---|
| Research Field |
Synthetic chemistry
|
|---|
| Research Institution | KYOTO UNIVERSITY |
|---|
Principal Investigator |
OSHIMA Koichiro Kyoto University, Graduate School of Engineering, Professor, 工学研究科, 教授 (00111922)
|
|---|
| Project Period (FY) |
1994 – 1995
|
| Keywords | Silacyclobutane / Silacyclopentane / Radical Cyclization / Triethylborane / Tributyltin Hydride / Mixed Acetal / Aldol Reaction |
|---|
| Research Abstract |
1.1-Allyloxy-2-bromo-1-phenylsilacyclopentane was synthesized by a ring-enlargement reaction of 1-allyloxy-1-phenylsilacyclobutane with LiCHBr_2. The treatment of 1-allyloxy-2-bromo-1-phenylsilacyclopentane with n-Bu_3SnH in the presence of a catalytic amount of Et_3B provided 2-oxa-1-silabicyclo [3.3.0] octane, which was converted into 1,3,6-triol by an oxidative cleavage of silicon-carbon bonds with H_2O_2. An intermolecular radical addition of 2-iodosilacyclopentane to acetylenic compounds afforded the corresponding iodoalkenes.
2.Treatment of ethyl benzoate or isopropyl formate with tert-butyldimethylsilyldibromomethyllithium gave alkyl silyl mixed acetal via 1,3-rearrangement of silyl group from carbon to oxygen. The reaction of the mixed acetals with allylsilane in the presence of Lewis acid afforded allylated ethers.
3.Treatment of 2-halo-2-trimethysilyloxirane with metal salts such as ZnCl_2, ZnBr_2, NaI,and AgBF_4 gave the corresponding alpha-haloacylsilanes in good yields. An addition of triethylborane to haloacylsilane provided boron enolate which reacted with aldehydes to give aldol type adducts with high stereoselectivity.
|
