A new alkaloid (proposed name, deoxyharringtonine) with significant antileukemic activity has been isolated from Cephalotaxus harringtonia (Forbes) K. Koch var. harringtonia cv. Fastigiata. Its structure has been established as either 2 or 3 by chemical and spectral methods. Total synthesis of the dicarboxylic acid side chain and esterification of its primary carboxyl group with natural cephalotaxine (1) yields 3: therefore, deoxyharringtonine must be 2. © 1972.