Synthesis of a Stereoisomer of Frullanolide Utilizing the Intramolecular Cyclization of<i>ω</i>-Formyl-2-alkenylsilane
作者:Chiaki Kuroda、Shigeru Shimizu、Takahiro Haishima、James Y. Satoh
DOI:10.1246/bcsj.66.2298
日期:1993.8
Synthesis of 10-epi-frullanolide (3) is reported via the intramolecular cyclization of ω-formyl-α-trimethylsilylmethyl-α,β-unsaturated ester. The cyclization precursor, ethyl (Z)-5-(2-formyl-1,3-dimethyl-2-cyclohexenyl)-2-trimethylsilylmethyl-2-pentenoate (17), was prepared from 2,6-dimethyl-2-cyclohexen-1-one through the dialdehyde monoacetal as the key intermediate. Cyclization of 17 with tetrabutylammonium fluoride produced the hydroxy ester having C(6α)–H and C(7β)–H, which was hydrolyzed, then subjected to Fujisawa’s lactonization to afford 3.
据报道,通过 ω-甲酰基-α-三甲基甲硅烷基甲基-α,β-不饱和酯的分子内环化合成了 10-epi-frullanolide (3)。环化前体 (Z)-5-(2-甲酰基-1,3-二甲基-2-环己烯基)-2-三甲基甲硅烷基甲基-2-戊烯酸酯 (17) 由 2,6-二甲基-2-环己烯制备-1-酮通过二醛单缩醛为关键中间体。 17与四丁基氟化铵环化生成具有C(6α)-H和C(7β)-H的羟基酯,将其水解,然后进行藤泽内酯化得到3。