| Budget Amount *help |
¥4,420,000 (Direct Cost: ¥3,400,000、Indirect Cost: ¥1,020,000)
Fiscal Year 2014: ¥1,820,000 (Direct Cost: ¥1,400,000、Indirect Cost: ¥420,000)
Fiscal Year 2013: ¥1,300,000 (Direct Cost: ¥1,000,000、Indirect Cost: ¥300,000)
Fiscal Year 2012: ¥1,300,000 (Direct Cost: ¥1,000,000、Indirect Cost: ¥300,000)
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| Outline of Final Research Achievements |
The first total synthesis of (+)-gregatin E and a new total synthesis of (+)-gregatin B was carried out. Key features of our synthetic approach involve a palladium-catalyzed cyclization-methoxycarbonylation of optically active propargylic acetate and a Suzuki-Miyaura coupling or CuTC-mediated coupling reaction. The absolute configuration of (+)-gregatin E (5R, 5’S) was determined.
Asymmetric cyclization-methoxycarbonylation of 1,1-diethynylacetate mediated by chiral palladium (II) complex afforded orthoesters in good yield with good enantioselectivity. Orthoesters were easily converted to franones and therefore the formal synthesis of gregatin B and E were achieved.
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