Grant-in-Aid for Scientific Research on Priority Areas (B)
|Allocation Type||Single-year Grants |
|Research Institution||University of Tsukuba |
HOSOMI Akira University of Tsukuba, Chemistry, Professor, 化学系, 教授 (00004440)
CHATANI Naoto Osaka University, Chemistry, AssociateProfessor, 大学院・工学研究科, 助教授 (30171953)
TAKAI Kazuhiko Okayama University, Chemistry, Professor, 工学部, 教授 (00144329)
OSHIMA Koichiro Kyoto University, Chemistry, Professor, 大学院・工学研究科, 教授 (00111922)
NISHIGUCHI Ikuzo Nagaoka T. & S. University, Chemistry, Professor, 工学部, 教授 (20026347)
HIRAO Toshikazu Osaka University, Chemistry, Professor, 大学院・工学研究科, 教授 (90116088)
|Project Period (FY)
1998 – 2000
Completed (Fiscal Year 2001)
|Budget Amount *help
¥2,700,000 (Direct Cost: ¥2,700,000)
Fiscal Year 2000: ¥900,000 (Direct Cost: ¥900,000)
Fiscal Year 1999: ¥900,000 (Direct Cost: ¥900,000)
Fiscal Year 1998: ¥900,000 (Direct Cost: ¥900,000)
|Keywords||Unstable Reactive Species / Stereoselective synthesis / Transition metal-catalyzed reactions / Redox systems / Srereocontrol / Samarium-mediated reactions / [3+2] Cycloaddition / Electron transfer process|
The following various successful results were ottained during this study between 1998-2001.
Symposiums are held at Sapporo in 1999 and Tsukuba in 2000.
1. Silicon-directed Cyclization of Vinylysilanes : Stereoselective Synthesis of Tetrahydrofurans and Tetrahydropyrans
Silicon-directed stereoselective syn addition of hydroxy group to olefinic double bond occurs intramolecularly in an acid-catalyzed cyclization of vinylsilanes bearing hydroxy group. The cyclization proceeds by stereospecific syn addition of the hydroxy group. Vinylsilanes, (Z)-5-silyl-4-penten-1-ols bearing a substituent on the methylene tether, smoothly undergo the acid-catalyzed cyclization to give trans-2,5-, cis-2,4-, and trans-2,3-disubstituted tetrahydrofurans, respectively, with moderate to high stereoselectivity.
2. New Synthetic Reactions induced by the Redox Systems including Transition Metals directed to Stereocontrol
3. Stereocontrol in the Transition Metal-Catalyzed Synthetic Reactions
4. Unprecedented Manganese-
Mediated Reactions : Generation of Non-Stabilized Carbonyl Ylids
Activated manganese generates nonstabilized carbonyl ylides from bis(chloromethyl) ethers as a precursor, and using this system with manganese as a reductant, the reactions of the ylides with electron-deficient dipolarophiles can be attained without the direct reduction of dipolarophiles by the reductant.
5. Manganese Ate Species : Generation and Reactions with Electrophiles
Trialkylmanganese(II) ate reagents, "R_3MnLi" reacted with iodomethylsulfides to produce thiomethylmanganese reagents, where the manganate serves as a reductant not an alkylation agent. The reductive behavior of trialkylmanganese(II) ate reagents provides a protocol for the direct generation of a new class of reagents, thiomethylmanganese reagents with structural variety, and the generated thiomethylmanganese reagents reacted with allyl bromides, enones and aldehydes.
6. Sterocontrol in the radical Reactions
7. Dynamic control of the reaction pathways in the Formation Reactions of Carbon-Carbon Bonds and Carbon-Silicon Bonds via Electron Transfer Process Less