| Co-Investigator(Kenkyū-buntansha) |
UCHIYAMA Masahiko Kanazawa University, Faculty of Pharmaceutical Sciences, Assistant Professor, 薬学部, 助手 (40277265)
武田 良文 金沢大学, 薬学部, 助手 (70311678)
TAMURA Osamu Kanazawa University, Faculty of Pharmaceutical Sciences, Associate Professor, 薬学部, 助教授 (30257141)
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| Research Abstract |
Radical cyclization was recognized as a valuable tool for the construction of cyclic compounds, and the methods have been widely employed in the field of organic synthesis including natural products synthesis. However, there are many ploblems which required solvation in this useful radical cyclizations. One of them is the controlling regiochemistry. If this problem is solved, the radical cyclization would be highly promising. A new method for generation of radical species is also required. We, therefore, examined several radical cyclizations in more details, and found the following evidences.
1)A new method for the synthesis of mappicine ketone, an antiherpesvirus compound, has been developed by using sulfur-directed 5-exo selective aryl radical cyclization. 2)A new method for the, synthesis of an analgesic(-)-aphanorphine has been developed by using sulfur-directed 6-exo selective aryl radical cyclization. 3)5-Endo and 4-exo selectivity in radical cyclization of N-(2-phenylthio and 2-phenyl-1-cyclohexenyl)-α-haloamides have been elucidated. 4)A radical cascade involving a 5-endo cyclization of α-amidoyl radicals has been found. 5)It was found that the use of iodine atom as a leaving group is not recommended for the 5-endo radical cyclization of N-vinylic α-haloamides. 6)A new synthesis of erythrinane skeleton which consisted of treatment of α-(methylthio)acetamides with Mn(OAc)_3 in the presence of Cu(II) was found, and the method was applied to the synthesis of 3-demethoxyerythratidinone, a naturally occurring Erythrina alkaloid.
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