... C The Chemical Society of Japan 1981 SYNTHETIC STUDIES TOWARD MAYTANSINOIDS1 PREPARATION OF THE OPTICALLY ACTIVE INTERMEDIATES FROM D-MANNOSE Minoru ISOBE*, Yoshiyasu ICHIKAWA, Masato KITAMURA and Toshio GOTO Laboratory of Organic Chemistry, Faculty of Agriculture, Nagoya University, Chikusa, Nagoya 464 Summary: Optically active intermediates (15 and 23) for maytansine were synthesized ...