Regio-and stereocontrolled terminal functionalization of protected 2-prenyl-and 2-geranylhydroquinones (2) was achieved by way of terminal methallylic sulfides (4), which were easily obtained via benzenesulfenyl chloride addition followed by dehydrochlorination or via allylic chlorination with SO2Cl2 followed by sulfenylation, leading to terminal trans-allylic alcohols (5) which are promising intermediates for the synthesis of polyisoprenoidquinones. In this transformation, interesting steric effects of the hydroquinone nucleus with the adjacent arylic methyl group influencing the site-selectivity in the reactions of the isoprenoid side chain were observed.
保护的2-烯丙基和2-
香叶烯基
氢醌(2)的区域和立体选择性末端官能化通过末端美克烯基
硫化物(4)实现,这些
硫化物可通过苯基
磺酰氯的加成反应后脱
氯化获得,或者通过SO2Cl2的烯丙基
氯化后进行亚砜化反应获得,最终转化为末端反式
烯丙醇(5),这些化合物是合成聚
异戊二烯酮的有前景的中间体。在这一转化过程中,观察到
氢醌核与邻近芳基甲基团之间的有趣立体效应,这影响了
异戊二烯侧链反应的位点选择性。