The following new results have been obtained :
1.New organozinc reagents and their Lewis-acid complexes were prepared by reaction of organozinc with Cu (I) slats. It is found that these new reagents were highly effective for the stereo-and regioselective 1,3-chirality transfer reactions of a vinyl group.
2.It is found that the above reagents can be prepared from both organolithium and Grignard reagents. Addition of LiCl stabilize the reagents.
3.It is found that the reaction of g-mesylor gamma-tosyloxy-alpha, beta-enoates can be transformed into alpha-vinyl-beta, gamma-enoates in a highly regio-and stereoselective manner.
4.Methods for potentially useful isomertization of gamma, delta-imino-alpha, beta-enoates by treatment with Pd (Ph_3) _4 at room temperature have been developed.
5.Four L-Leu-PSI [ (E) CH=CH ] L-Leu, L-Leu- PSI [ (E) CH=CH ] D-Leu, L-Val-PSI [ (E) CH=CH ] L-Leu, and L-Val-PSI [ (E) CH=CH ] D-Leu isosteres have been synthsized. Incorporation of these dipeptide isosteres into polypeptides can be done in a highly effective manner. These isosteric peptides showed very high bombesin antagonist activity.