Synthesis of (R)-(-)-3-Methoxymethyl-3-propyl-3,4-dihydrocoumarin from a Chiral Michael Adduct: Absolute Configurations of the Allylated Products of Enantioselective Radical-Mediated Reactions.
作者:Masatoshi MURAKATA、Yusuke MIZUNO、Hiromi YAMAGUCHI、Osamu HOSHINO
DOI:10.1248/cpb.47.1380
日期:——
(R)-3-Methoxymethyl-3-propyl-3, 4-dihydrocoumarin was synthesized, starting from a chiral Michael adduct [(S)-methyl 2, 3-dihydro-1-oxo-2-(3-oxobutyl)-1H-indene-2-carboxylate], in order to determine the absolute configurations of the products obtained by enantioselective radical-mediated allylation. Aldol cyclization of the Michael adduct proceeded smoothly with suppression of the retro Michael reaction to afford an optically active cyclized product. The Baeyer-Villiger reaction of (R)-2-methoxymethyl-2-propylindanone in the presence of BF3·Et2O afforded the desired dihydrocoumarin.
(R)-3-甲氧基甲基-3-丙基-3,4-二氢香豆素是从手性迈克尔加成物((S)-甲基2,3-二氢-1-氧代-2-(3-氧代丁基)-1H-茚-2-羧酸酯)合成的,目的是确定通过手性自由基介导的烯丙基化反应得到的产品的绝对构型。迈克尔加成物的醛缩环反应在抑制逆迈克尔反应的情况下顺利进行,从而得到具有光学活性的环化产物。在BF3·Et2O存在下,(R)-2-甲氧基甲基-2-丙基茚满酮的Baeyer-Villiger反应得到所需二氢香豆素。