Grant-in-Aid for Scientific Research on Priority Areas (B)
|Allocation Type||Single-year Grants|
|Research Institution||Kyushu University|
KATSUKI Tsutomu Kyushu University, Chemistry, Professor, 大学院・理学研究院, 教授 (40037271)
HAYASHI Masahiko Yamaguchi University, Chemistry, Associate Professor, 理学部, 助教授 (60192704)
KAWABATA Takeo Kyoto University, Chemistry, Associate Professor, 化学研究所, 助教授 (50214680)
MIYASHITA Masaaki Hokkaido University, Chemistry, Professor, 大学院・理学研究科, 教授 (50006326)
OHBA Masaaki Kyushu University, Chemistry, Assistant Professor, 大学院・理学研究院, 助手 (00284480)
IRIE Ryo Kyushu University, Chemistry, Assistant Professor, 大学院・理学研究院, 助手 (70243889)
ITO Yoshio Kyushu University, Chemistry, Associate Professor, 大学院・理学研究院, 助教授 (00221086)
MATSUMURA Yoshihiro Nagasaki University, Pharmacy, Professor, 薬学部, 教授 (60026309)
|Project Period (FY)
1998 – 2000
Completed(Fiscal Year 2001)
|Budget Amount *help
¥69,500,000 (Direct Cost : ¥69,500,000)
Fiscal Year 2000 : ¥22,800,000 (Direct Cost : ¥22,800,000)
Fiscal Year 1999 : ¥23,000,000 (Direct Cost : ¥23,000,000)
Fiscal Year 1998 : ¥23,700,000 (Direct Cost : ¥23,700,000)
|Keywords||Dynamic stereocontrol / Metallosalen complexes / Entropy-controlled reactions / Acyclic stereocontrol / Molecular oxygen / Glucal / Electrode reaction / Memory of chirality / 分子間相互作用 / 立体化学制御 / 不斉誘起能 / シクロプロパン化 / メソ型化合物 / モノベンゾイル化 / 配位子配座制御 / OH-π相互作用 / 鎖状制御 / シアノ糖 / 選択的アシル化|
Dynamic control of intermolecular interaction is indispensable for achieving highly stereocontrolled reactions. We have developed various new stereocontrolled reactions on the basis of new knowledge on the factors controlling intermolecular reactions.
(1) Study with metallosalen complexes
The X-ray structural analysis of metallosalen complexes clarified that conformation of the salen ligands is strongly influenced by weak-bond interactions such as OH-π and CH-π interactions and by the presence or absence of a donor ligand. With this knowledge, highly cis- and enantio-selective cyclopropanation was achieved for the first time. Furthermore, new type of asymmetric catalysts activated by photo-irradiation were introduced and, with these complexes, catalytic asymmetric oxidation using molecular oxygen as the terminal oxidant was developed.
(2) New methodologies for acyclic stereocontrol
Stereospecific and regioselective epoxide-ring opening using new aluminum and borane reagents enabled efficie
nt construction of consecutive asymmetric centers. High efficient construction of chiral quaternary carbons was also developed. With these reactions as key steps, various natural products of complex architectures were synthesized in a highly straightforward manner.
(3) Asymmetric induction based on dynamic chirality of enolate structure
Direct α-alkylation of optically active α-amino acids was achieved in an enantiospecific manner in the absence of any external chiral sources. Newly introduced nucleophylic catalyst bearing p-aminopyridine moiety enabled highly enantiomer-differentiating acylation. The origin for the observed selectivity was attributed to enantiomer-selective acceleration.
(4) Transition metal catalysts in stereoselective carbohydrate synthesis
Various carbohydrate derivatives were synthesized efficiently from protected and unprotected glucals by using transition metal catalysts.
(5) Desymmetrization of meso-diols and memory of chirality in carbenium ion
Asymmetric desymmetrization of meso-diols was achieved efficiently by mono-acylation using chiral binaphthyltin dibromide as a catalyst. Optically acive α-amino acids were converted into optically active aminals via the corresponding acylinium ions in the absence of any external chiral sources. These results disclosed that memory of chirality can be observed in the reactions proceeding through a carbenium intermediate. Less