D-グルコースから誘導される新しいキラルシントン : 酸化型ジメチル分枝構造をもつピラノシドの合成

概要

論文の詳細を見る
Reactions of several different kinds of methyl-branched pyranosides were investigated in order to establish new effective routes to carbohydrate chiral synthons having oxygenated dimethyl-branched structure, which are often included in biologically active natural products. While reactions of methyl-branched pyranosides having allylic acetate structure (<I>O</I>-acetylated enopyranosides) and methyl-branched anhydropyranosides with lithium methylcuprates (I) gave 1, 3- and 1, 2- dimethyl structures, respectively, the following three methods were proved to be effective for construction of <I>gem</I>-dimethyl structure in the pyranoside ring : (1) conjugate addition of lithium methylcuprates (I) to methyl-branched enolones, (2) enolate methylation of methyl-branched uloses with lithium diisopropylamide and methyl iodide, and (3) hydrogenolysis of spiro- cyclopropane derivatives, which were derived from corresponding uloses via exomethylene derivatives. Stereochemical aspects in some of these reactions were also discussed.
社団法人有機合成化学協会の論文