摘要
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-methylformanilide 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（methylenedioxy）naphthalene 9 in 48% yield. After the electrooxide deprotection of 8, （±）shikonin 1 was prepared in high yield.
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-methylformanilide 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（methylenedioxy）naphthalene 9 in 48% yield. After the electrooxide deprotection of 8, （±）shikonin 1 was prepared in high yield.
