利用掌性的雙烯雙醇35與(RS)乙酸庚-6-烯-2-酯63為起始物合成 (5R,11R)-Cladospolide D (1a) 和 (5R,11S)-Cladospolide D (1b)。保護後之35先與丙烯酸甲酯進行第一次的交叉置換反應，然後在羥基上作保護基的轉換再與烯63進行第二次的交叉置換反應來導入C11的掌性中心。然後利用正丁硫醇進行Michael addition，接著氫化雙鍵，再以m-CPBA和DBU重新生成共軛雙鍵。酯基水解後之酸進行Yamaguchi內酯化反應得到十二員環的內酯。選擇性去除保護後氧化得到酮，最後再去除保護基得到1a和1b。鑑定天然物Cladospolide D結構為1b，即 (6R,12S,E)-6-hydroxy-12-methyloxacyclododec-3-ene- 2,5-dione。 (5R,11R)-Cladospolide D (1a) and (5R,11S)-Cladospolide D (1b) was synthesized using diene 35 and (RS)-hept-6-en-2-yl acetate 63 as the strating materials. The first cross metatheses (CM) reaction of protected 35 with methyl acrylate and the following deprotection provided the ester 57. Then the second cross metatheses reaction of ester 57 and alkene 63, Michael addition with n-butanethiol, hydrogenation, oxidation and elimination by m-CPBA and DBU, regenerated the α,β-unsaturated ester. After hydrolysis of the ester group and the Yamaguchi lactonization, the twelve-membered lactone was obtained. Selective deprotections and oxidation provided the target 1a and 1b. Therefore, the structure of Cladospolide D is established as (6R,12S,E)-6-hydroxy-12- methyloxacyclododec-3-ene-2,5-dione (1b)。
