A new total synthesis of (2S,3R)-3-hydroxy-3-methylproline has been performed via a key intermediate chiral pyrroline N-oxide, obtained from (R)-citramalic acid. This nitrone underwent nucleophilic addition of furyllithium with complete stereoselectivity through a preferential attack anti to the methoxymethoxy group. The correct stereochemistry was established through an oxidation−reduction sequence
(2S,3R)-3-羟基-
3-甲基脯氨酸的新全合成已通过关键中间体手性
吡咯啉 N-氧化物进行,该中间体从 (R)-柠
苹果酸获得。该硝酮通过抗甲氧基甲氧基的优先攻击以完全立体选择性进行
呋喃基
锂的亲核加成。正确的立体
化学是通过氧化还原序列建立的,这允许在 C-2 处反转构型。(© Wiley-
VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)