Annual Research Report, 1998


The objective of this research group is the development of novel reactions that will generate novel strategies for formation and cleavage of chemical bonds connected to a carbon atom. To this end, we are studying the behavior of molecules of complex electronic and structural properties such as open shell reactive intermediates, polyatomic compounds and chemical environments where reactions take place.

(1) Creation of new organic functional molecules by way of fullerene functionalization

(2) Olefinic aldol reaction

(3) Mechanistic studies on organocopper reactions


(1) Creation of new organic functional molecules by way of fullerene functionalization

We reported a remarkable reaction, with which three organic groups can be introduced to [70]fullerene in quantitative yield. The product C70R3H possesses a spherical p-electron system and an indene, which can be converted to MLn(h5-C70R3). We are aiming at development of catalysts and materials out of these compounds. Theoretical and electrochemical studies on the properties of these compounds indicated that the cyclopentadiene and the p-electron moiety are conjugated through the inner sphere of the fullerene core.

A-6) J. Am. Chem. Soc., 120, 8285-8286 (1998)

(2) Olefinic aldol reaction

We are also focusing on the addition of organometallics to an olefin, which will generate useful synthetic reactions. We found that the use of a zincated hydrazone of a ketone realizes the olefinic aldol reaction, where in the enolate unit adds in good yield to an olefin. This type of the reaction is by itself an endothermic reaction and has never been considered to be feasible. Thus, addition of the hydrazone to ethylene generates a new reactive species having electrophilic and nucleophilic centers in the same molecule.

A-1) Tetrahedron Lett., 39, 2157-2158 (1998)

A-8) J. Am. Chem. Soc., 120, 13334-13341 (1998)

(3) Mechanistic studies on organocopper reactions

It was in the 1940Ős, when the synthetic utility of organocopper reactions was first recognized. Since then, copper has been established to be the most important transition metals. The mechanisms of these reactions, however, was rather obscure for 50 years since the discovery. We have resolved the problem with the aid of large scale molecular orbital calculations, and proposed mechanistic pathways for conjugate addition to unsaturated aldehydes and alkyation of alkyl halide.

The structures of the polymetallic intermediates and transition states not only account for various experimental facts but provide guide lines for further design of useful reactions including asymmetric reactions. We also found that the cooperative effects of polymetallic clusters are also important in Simmons-Smith reaction and related organozinc reactions.

A-3) J. Am. Chem. Soc., 120, 5844-5845 (1998)

A-5) J. Am. Chem. Soc., 120, 8273-8274 (1998)

A-11) Chem. Eur. J., 5, 1534-1543 (1999)