The various methods for the umpolung of carbonyl compounds ( aldehydes and ketones ) secondary amines and the most frequently used umpolung reagents are introduced .

先介绍了羰基化合物（醛、酮）的 极 性 转换的各种方法， 然后 谈到胺的 极 性 转换方法和最常用的极性转换试剂。

The concept and some applications about umpolung were expounded and some new methods about the application of the umpolung were given .

极 性 转换方法是一种重要的有机合成新方法，对 极 性 转换的概念和应用 作了论述，并对一些极性转换的新技术作了简。

In this article the fundamental concept of umpolung and its role in organic synthesis are briefly discussed .

本文主要论述 极 性 转换的基本概念和它在有机合成中的作用。

The organic compounds unable to be synthesized under normal reaction can be fulfilled by means of umpolung .

在有机合成中一些不能用常规反应合成的有机化合物可以通过 极 性 转换的方式来完成。