Budget Amount *help |
¥3,600,000 (Direct Cost: ¥3,600,000)
Fiscal Year 2006: ¥1,400,000 (Direct Cost: ¥1,400,000)
Fiscal Year 2005: ¥2,200,000 (Direct Cost: ¥2,200,000)
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Research Abstract |
Soft metal-hard anion conjugated asymmetric catalysts, such as CuF and CuOR display unique reactivity. Combined with versatile carbon nucleophiles, such as allylsilanes, allylboronates, ketene silyl acetals, alkenylsilanes, alkenylboronates, arylsilanes, and arylboronates, they quickly transfer hard anion onto hard metals (Si and B). Resulting Cu silicates or borates can transfer soft carbon nucleophiles back to soft Cu, generating highly nucleophilic Cu-based nucleophiles, such as allylcopper, copper enolates, alkenylcopper, and aiylcopper. Chiral nucleophiles are to be generated using chiral phosphines. The Cu-based nucleophiles are highly reactive, and catalytic asymmetric addition to ketones and ketoimines were realized. The concept of soft metal-hard anion conjugated asymmetric catalysis was extended to three-component reaction of an allenic ester, ketones, and pinacolboronate. From the Cu catalyst and pinacolboronate, copper hydride was generated through transmetalation. The copper hydride reduced allenic ester chemoselectively, and copper enolate was generated. The copper enolate added to ketones enantioselectively. Importantly, reaction pattern was tunable by the chiral phosphine structure. Using DTBM-SEGPHOS as a ligand, the reaction proceeded through γ-cis selective manner. Whereas, α-adduct was selectively produced using Taniaphos as a ligand. These results demonstrated that the reaction pattern of the multi-component reaction can be controlled by the chiral catalyst.
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