General Method for Asymmetric Synthesis of α-Methylsulfinyl Ketones: Application to the Synthesis of Optically Pure Oxisuran and Bioisosteres
作者:H. El Ouazzani、N. Khiar、I. Fernández、F. Alcudia
DOI:10.1021/jo961038q
日期:1997.1.1
compounds led to some epimerization at sulfur. This loss of chirality was circumvented by reacting the alpha-lithio derivatives of the N,N-dimethylhydrazones derived from these ketones with either the (R)- or the (S)-methanesulfinate of diacetone D-glucose, to yield the corresponding alpha-(methylsulfinyl)methylhydrazones, with complete inversion of chirality at sulfur. Hydrolysis of the resulting
记载了合成的免疫抑制药奥沙苏兰[1,(甲基亚磺酰基)甲基2-吡啶基酮]的首次不对称合成。使用DAG方法进行关键的缩合步骤,以光学纯净的形式高效合成了两种对映异构体。尝试将芳基甲基酮的金属烯醇盐与手性亚磺酰基化合物偶合,导致在硫上有些差向异构。通过使由这些酮衍生的N,N-二甲基hydr的α-硫代衍生物与双丙酮D-葡萄糖的(R)-或(S)-甲亚磺酸盐反应,制得相应的α- (甲基亚磺酰基)甲基hydr,在硫上具有完全的手性反转。用氯化铜(II)水解所得,得到光学纯形式的1。通过制备旋光的奥苏兰类似物2-4证明了该方法的普遍性,其中吡啶基部分分别被苯基,呋喃基和噻吩基部分取代。在研究β-酮亚砜的外消旋混合物所建立的条件下,使用手性位移试剂通过质子NMR光谱法测定这些产物的光学纯度。