The total synthesis of majusculamide D (MJS-D) is described, a lipopentapeptide originally isolated from Lyngbya majuscula and reisolated from a Moorea sp. MJS-D possesses selective and potent cancer cell toxicity. A scalable and convergent strategy with a minimal number of purifications produced significant quantities of MJM-D for in vivo evaluations. The absolute configuration of the 1,3-dimethyl-octanamide motif was determined by synthesis of this fragment via ZACA chemistry.