| Budget Amount *help |
¥13,300,000 (Direct Cost: ¥13,300,000)
Fiscal Year 2006: ¥2,100,000 (Direct Cost: ¥2,100,000)
Fiscal Year 2005: ¥4,500,000 (Direct Cost: ¥4,500,000)
Fiscal Year 2004: ¥6,700,000 (Direct Cost: ¥6,700,000)
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| Research Abstract |
There are many reactions of 1, 2-propadienes(allenes), which have cumulated double bond moieties, as unique synthetic reagents. Among them, the features of the cumulated double bond are effectively utilized, that cannot be achieved by simple double or triple bond. In this research, I recognize vinylidene and allenylidene complexes as metal analogue of 1, 2-propadienes and 1, 2, 3-butatriene, respectively, and pay attention to the reactivity of carbon-carbon double bond in metallacumulenes. I plan to search for synthetic reactions that make the best use of their characteristics, and that use metallacumulenes as two or three carbon unit.
I first examined the synthesis of vinylidene complexes from rhodium and iridium ones, which are known to be relatively electron-rich metals. According to the conventional methods, I tried to prepare them from low valent rhodium complexes and terminal alkynes via isomerization along with a hydrogen transfer. I failed but obtained multicyclic compounds by cycloaddition of alkyne moieties. Thus, I focused on the development of low valent late transition metal catalyzed-cycloaddition of alkynes and alkenes, especially enantioselective reaction using chiral metal catalysts.
For example, transition metal-catalyzed[2+2+2] cycloaddition is a well-established protocol for the construction of six-membered ring systems. I developed a new type of enantioselective[2+2+2] cycloaddition for the synthesis of quaternary carbon stereocenters. The intramolecular reaction of various 1, 4-diene-ynes proceeded using a chiral rhodium catalyst and tricyclic compounds possessing a strained bicyclo[2.2.1] heptene skeleton or bicyclic cyclo-1, 3-dienes were obtained, depending on the substituent on the 1, 4-diene moiety.
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