A Novel Total Synthesis of ( )Shikonin

A novel total synthesis of (±)shikonin 1 was presented. The key intermediate 6 was achieved by the formylation of 1,8:4,5-bis(methylenedioxy)naphthalene 5 with N-methylforma-nilide in good yield. It was first reported that the addition of prenyllithium to 2-formyl-1,8:4,5-bismethylenedioxy naphthalene 6 gave 2-(1-hydroxy-4-methylpentyl) 1,8:4,5-bis(methylenedioxy)naphthalene 8 in 45% yield and 2-(1-hydroxy-2,2-dimethyl-3-butenyl)-1,8:4,5-bis(methylene-dioxy)naphthalene 9 in 48% yield. After the electrooxide deprotection of 8, (±)shikonin 1 was prepared in high yield.