| Budget Amount *help |
¥3,500,000 (Direct Cost: ¥3,500,000)
Fiscal Year 2006: ¥1,500,000 (Direct Cost: ¥1,500,000)
Fiscal Year 2005: ¥2,000,000 (Direct Cost: ¥2,000,000)
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| Research Abstract |
In this project, I succeeded to control the regioselectivity and diastereoselectivity in the transition metal catalyzed allylic alkylation of allyl acetates, and achieved to construct chiral quaternary amino acid and its analogues.
I discovered the regio- and diastereo-selectivity in the palladium-catalyzed allylic alkylation of (R)- or (S)-2-acetoxy-4-phenyl-3-butene with N-(diphenylmethylidene)glycinate and N-(diphenylmethylidene)alaninate was highly control by using 2-(diphenylphosphino)benzoic acid. For example, the reaction with N-(diphenylmethylidene)glycinate formed the chiral amino acid analogues which possessing vicinal two chiral tertiary carbon centers at the α and β positions with up to 99% reio- and diastereo-selectivities. The alkylation product was further converted to chiral aspartic acid analogues in 7 steps. I also succeeded to control the regio- and diastereo-selectivity in the reaction with N-(diphenylmethylidene)alaninate, and constructed the amino acid analogues wh
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ich possessing vicinal chiral quaternary and tertiary carbon centers at the α and β positions with up to 99% reioselectivity and up to 95% diastereoselectivity. The chiral alkylated product also converted chiral 2,3-dimethylaspartic acid in 7 steps.
Furthermore, I examined the similar stereoselective allylic alkylation with azlactones, and I also succeeded to control the regioselectivity and diastereoselectivity. In the reaction of azlactones, I confirmed the 2-(diphenylphosphino)benzoic acid was again key ligand to control the desired stereoselectivities. For example, the reaction with 2-methyl substituted azlactone proceeded in perfect regioselecitity and 98% diastereoselectivity, and demonstrated to convert it to chiral quaternary aspartic acid analogues. Furthermore, I found the triphenylarsine also an effective ligand for this stereoselective allylic alkylations, and 2-(diphenylphosphino)benzoic acid and triphenylarsine gave different diastereoselectivity.
Totally, I succeeded to control the regio- and diastereo-selectivities in the palladium-catalyzed allylic alkylation of (R)- or (S)-2-acetoxy-4-phenyl-3-butene with several amino acid analogues. The coupling product which possessing vicinal two chiral carbon centers or vicinal chiral quaternary and tertiary carbon centers at the α and β positions were converted chiral quaternary amino acids. Less
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