Details of the synthesis method of the tumor promoters teleocidin B-3 (3), teleocidin B-4 (4) and dihydroteleocidin B-4 (9) (= dihydroteleocidin B) from (S)- and (R)-methyl N-methyl-N-[7-(3,6,7-trimethyl-1,6-octadien-3-yl)-4-indolyl]-L-valinates (20b and 20a) are presented.