Regio- and stereoselective terminal allylic carboxymethylation of gem-dimethyl olefins. Synthesis of biologically important linear degraded terpenoids.
作者:YUKIO MASAKI、KAZUHIKO SAKUMA、KENJI KAJI
DOI:10.1248/cpb.33.1930
日期:——
gem-Dimethyl olefins (III) were transformed regiospecifically to the terminal β-methallyl sulfides (IV) bearing the methoxycarbonylmethyl substituent on the sulfur atom via (A) methoxycarbonylmethanesulfenyl chloride addition followed by dehydrochlorination or (B) allylic chlorination with SO2Cl2 followed by sulfenylation with methyl thioglycolate. Treatment of the sulfides (IV) with tert-BuOK or NaH in N, N-dimethylformamide or dimethyl sulfoxide at room temperature gave stereoselectively the sulfur-free esters (V) through a novel one-pot desulfurizative [2, 3]-sigmatropic rearrangement. By utilizing this method, biologically and pharmacologically important linear degraded terpenoids, a diol component (1) of the pheromonal secretion of the queen butterfly and several ω-quinoid acids (4, n=1, 2) and (5, n=1, 2), which are metabolites of polyisoprenoidquinones, were synthesized.
gem-Dimethyl 烯烃 (III) 通过 (A) 向甲氧基羧甲烷磺酰氯的加成反应后去氯化,或 (B) 与 SO2Cl2 的烯丙基氯化反应,再与甲基硫代甘油酸酯进行硫烯基化反应,特异性地转化为带有甲氧基羧甲基取代基的末端 β-美沙酰硫化物 (IV)。在室温下,用 tert-BuOK 或 NaH 处理这些硫化物(IV)于 N,N-二甲基甲酰胺或二甲基亚砜,得到无硫的酯 (V),这一过程通过一种新颖的一锅式脱硫 [2,3]-σ-转位重排实现。利用该方法,合成了生物和药理学上重要的线性降解萜烯,蝴蝶女王的信息素分泌物中的二醇成分 (1),以及几种 ω-醌酸 (4, n=1, 2) 和 (5, n=1, 2),这些都是多异戊二烯醌的代谢物。