Studies on total synthesis of bioactive natural products chaetomellic acid A,7(Z)-nonadecadiene-2-3-dicaboxylicacid,2-(beta-carboxyethyl)-3-octylmaleic anhydride,2-3 carboxymethyl-3-hexymaleic anhhydride, nostoclide 1,sarkomyvin, homosarkomycin, ......