∆9-Tetrahydrocannabinol 1 and its isomers were synthesized via domino-type methodology. The first approach, leading to (±)-1, relies on the Mo(IV)-catalyzed, one-pot cascade reaction of citral (4) with olivetol (15), affording (±)-∆9-tetrahydrocannabinol as a 69 : 31 mixture of the trans- (natural) and cis-isomers in 20% yield. The alternative approach, leading to natural (-)-1, commenced with epoxidation of (+)-limonene (R)-(+)-16; opening of the resulting cis-epoxide 17 with PhSeNa, followed by elimination, afforded tertiary alcohol 21, whose acetate 22 was treated with olivetol 15 in the presence of Mo(II) catalyst IV to afford (-)-1 in 52% yield.
∆
9-
四氢大麻酚1及其异构体是通过多米诺式方法合成的。第一种方法,得到(±)-1,依赖于Mo(IV)催化的
柠檬醛(4)与
橄榄醇(15)的一锅串联反应,产率为20%,生成(±)-∆
9-
四氢大麻酚,其中包含69:31的
trans-(天然)和
cis-异构体混合物。另一种方法,得到天然(-)-1,首先对
(+)-柠檬烯(R)-(+)-16进行环氧化,然后用PhSeNa打开产生的
cis-环氧化合物17,随后消除作用,得到
三级醇21,其
醋酸酯22在Mo(II)催化剂IV存在下与
橄榄醇15反应,产率为52%,得到(-)-1。