The key step in the synthesis is Wittig coupling of farnesyltriphenylphosphonium bromide (8) with ethyl 2-oxo-3-methyl butyrate (3). (3) was prepared by Grignard reaction of ethyl oxalate with iso-propylmagnesium bromide.

• 其中关键步骤是溴化法呢基三苯基?(8)和2-氧代-3-甲基丁酸乙酯(3)的Wittig反应。