Development and Application of the Highly Efficient and Highly Stereoselective Synthetic Methods for Optically Active Cyelic Compounds by Asymmetric cycloaddition Reactions

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It is strongly required to develop a practical and efficient method for the construction of chiral molecules to explore new biologically active medicines and agricultural chemicals. It is obvious that the design of the specific chiral environment utililzing the chiral auxiliaries whose both enantiomers are easily available provides a useful way to prepare various optically active chemicals. Among such chiral auxiliaries, tartaric acid ester is one of the most promising and readily available candidates.In this research, a new and novel chiral system possessing two metal centers utilizing tartaric acid esters was designed ; that is, if two reactants are bound to two different metal centers of the dialkoxide derived from tartaric acid ester, which might actually form the rigid 5/5-fused bicyclic dinucleating structure, they might be ideally oriented and/or activated by the metals and the following reaction might proceed in an enantioselective manner to afford the corresponding optically active products. According to this hypothesis, we could develop an asymmetric Simmons-Smith reaction, asymmetric 1,3-dipolar cycloaddition reactions of nitrile oxides and nitrones. Easy availability of (R,R)- and (S,S) -tartaric acid esters has now made it possible to prepare both enantiomers of the required chemicals by quite simple procedures.