Chemistry of zamoranic acid. Part IX homochiral synthesis of polygodial and warburganal from 17-acetoxy-7-labden-15-ol
作者:Julio G. Urones、Isidro S. Marcos、Belen Gómez Pérez、Anna M. Lithgow、David Díez Patricio M. Gómez、Pilar Basabe、Narciso M. Garrido
DOI:10.1016/0040-4020(94)01061-4
日期:1995.2
14,15-dinor-17-acetoxy-7-labden-13-one, 4 was prepared from zamoranic acid methyl ester 5. Photochemical cleavage of 4 gave 12-acetoxy-7,9(11)-drimadiene, 3, in 75% overall yield. The chemo- and diastereoselective epoxidation of 3 afforded 12-acetoxy-9α and 9β(11)-epoxy-7-drimene, 17 and 18 in 4:1 ratio. Ring-opening of 17 (or the mixture ) using BF3·Et2O or ring-opening of the mixture lead to the
14,15-二也不-17-乙酰氧基-7- labden-13酮,4是从zamoranic酸甲酯制备5。光化学裂解4得到12-乙酰氧基-7,9(11)-双嘧二烯3,总产率为75%。的化疗和非对映选择性环氧化3,得到12乙酰氧基9α和9β(11) -环氧-7- drimene,17和18在4:1倍的比例。开环的17(或混合物使用BF)3 ·的Et 2 O或的混合物开环导致polygodial的合成前体:(9 - [R)-12-乙酰氧基drimen -11-人,20,非对映异构体过量90%。二烯3的化学和非对映选择性顺式羟基化反应产生了Warburganal9α,11,12-trihydroxy-7-drimene的合成前体29,收率47%。杂多醛和华宝醛分别由氮杂酸酯酸甲酯制备,总收率分别为55%和27%。