Regioselective Synthesis of Prenylphenols. Syntheses of Naturally Occurring 4′-Alkenyloxy-2′,6′-dihydroxy-3′-(3-methyl-2-butenyl)acetophenones
作者:Masao Tsukayama、Makoto Kikuchi、Yasuhiko Kawamura
DOI:10.1246/cl.1994.1203
日期:1994.7
The palladium-catalyzed coupling reaction of 4′,6′-bis(benzyloxy)-3′-iodo-2′-tosyloxyacetophenone with 2-methyl-3-butyn-2-ol gave 4′,6′-bis(benzyloxy)-3′-(3-hydroxy-3-methylbutynyl)-2′-tosyloxyacetophenone (7). Dehydration of the benzoate obtained via two steps from 7 gave the 3′-prenylacetophenone, which was converted into 4′,6′-dihydroxy-3′-prenyl-2′-tosyloxyacetophenone (12). Respective geranylation
4',6'-双(苄氧基)-3'-碘-2'-甲苯磺酰氧基苯乙酮与2-甲基-3-丁炔-2-醇的钯催化偶联反应得到4',6'-双(苄氧基) -3'-(3-羟基-3-甲基丁炔基)-2'-甲苯磺酰氧基苯乙酮 (7)。从 7 中通过两个步骤获得的苯甲酸酯脱水得到 3'-异戊二烯基苯乙酮,将其转化为 4',6'-二羟基-3'-异戊二烯基-2'-甲苯磺酰氧基苯乙酮 (12)。12 分别进行香叶基化和异戊二烯化,然后水解得到 4'-香叶氧基-和 4'-异戊二烯氧基-2',6'-二羟基-3'-异戊二烯基苯乙酮(1 和 2)。提出为 2'-烯氧基异构体的天然异戊二烯基苯乙酮的结构分别修改为 1 和 2。