（R）和（S）—2甲基戊酸的合成

使用Ｄ－（－）樟脑衍生物－莰烷－２，１０－磺内酰胺为原料，以Ｎ－烷酰基莰烷－２，１０－磺内酰２胺与碘代烷基化合物进行不对称烷基化反应为关键步骤，共经３步成功地合成出（Ｒ）和（Ｓ）－２－甲基戊酸，其光学纯度大于９５％ｅ．ｅ。本文合成方法具有合成步骤短，产率高，反应条件温和及手性助剂可回收利用等优点，是一种合成各种２－甲基链烷酸的简捷，有效的好方法。

Simple synthesis of ( R ) and ( S ) 2 methyl valeric acid

In this paper, ( R ) and ( S ) 2 methyl valeric acids were synthesized by three step reaction from D (-) camphor derivate (-) bornane 2,10 sultam (2), the key step for the total synthesis involved asymmetric alkylation of N acylbornane 2,10 sultam (3) with alkyl iodide (4). The enantiomeric excess of the total synthesis is over 95%. This method has advantages of short route, high yield, mild condition and reusability of chiral auxiliary, and a new efficient method is presented for the synthesis of 2 methyl alkanoic acid.