Annual Research Report, 1995

The aim of the research in these laboratories is to create new methods for formation and cleavage of carbon covalent bonds by controlling the dynamic properties of functional organic molecules. Special focus is currently placed on open shell reactive species having diverse electronic states, poly element organometallic species, and functional molecules capable of controlling the environment surrounding the reaction center.

(1) Design and mechanism of open shell molecules

(2) Design and mechanism of organometallic reactive species

(1) Design and mechanism of open shell molecules

We have designed high yield synthetic reactions by defining the factors controlling the electronic states of open shell organic molecules such as biradicals. We have thus developed new synthesis of carbocyclic 5-membered rings, the synthesis of radio-labeled water-soluble fullerenes and the synthesis of deuterium-labeled nucleic acids. The radio-labeled fullerene led to the first elucidation of pharmacokinetic behavior of fullerenes in the body.

A-8)Chemistry & Biology, 2, 385-389 (1995).

A-18) Angew. Chem. Int. Ed. Engl., 34, 2154-2156 (1995).

(2) Design and mechanism of organometallic reactive species

Taking the efficiency of asymmetric synthesis as an experimental probe, we have develop new synthetic reactions using organocopper, organozinc and metal carbene complexes. The first example of efficient asymmetric carbometallation of isolated olefins was achieved with the aid of optically active allylic zinc reagents.

A-11) J. Am. Chem. Soc., 117, 1179-1180 (1995).

Ab initio molecular orbital calculations are being carried out side by side with the experimental bench work in the laboratories. We have elucidated the factors controlling the stereochemistry of chelation controlled carbonyl addition reactions, which is playing a key role in organic synthesis.

A-12) J. Am. Chem. Soc., 117, 5055-5065 (1995).

Ligand effects play important roles in catalytic reactions. We have studies various asymmetric reactions using "trap" ligands, and also reported the initial studies on the new project dealing with catalytic reactions responding to external stimuli.

A-13) J. Am. Chem. Soc., 117, 9602-9603 (1995).