Development of a selective hydroxylation, amination and alkylation of prochiral CH2-groups via sequential Ru-catalysis

在该项目中，报告了一个旨在开发选择性C-H功能化系统的计划，该系统在某种程度上是对现有程序的补充。与现有方法不同，官能团将不是氧化体系的一部分，而是通过经典的羰基转化引入。为了开发这一体系，氢自转移催化的基本概念将与Ru催化的C-H氧化和还原顺序相结合。首先，阳离子(P^N^N^P)Ru(乙腈)Cl-络合物将用于亚甲基氧化成酮，在加氢或转移加氢条件下，该酮将被相同的催化剂还原。这一过程可被视为CH2-基团的选择性单羟基化，并应进一步阐述为一种广泛适用的过程，并特别关注对映体选择性版本的开发。此外，原位生成的酮可以类似于氢自转移催化与胺、C-H-酸性羰基或醛反应生成相应的缩合产物，这些缩合产物可以通过加氢或转移加氢条件进行还原。这种一锅法将代表亚甲基的选择性胺化或烷基化。

In the project a program aiming to develop a system for the selective C-H functionalisation, that is somewhat complementary to the existing procedures, is reported. In contrast to the existing methodologies the functional group will not be part of the oxidizing system but will be introduced using classical carbonyl group transformations. In order to develop this system the basic concept of the hydrogen-autotransfer-catalysis will be combined with a sequential Ru-catalyzed C-H oxidation and reduction. Initially, the cationic (P^N^N^P)Ru(acetonitrile)Cl-complex will be used for the oxidation of a methylene group into a ketone, which will be reduced by the same catalyst under hydrogenation or transferhydrogenation conditions. This process might be regarded as a selective mono-hydroxylation of a CH2-group and shall further be elaborated into a broadly applicable process with a special focus on the development of an enantioselective version. Moreover, the in-situ generated ketones could react in analogy to the hydrogen-autotransfer catalysis with amines, C-H-acidic carbonyl groups or aldehydes to the corresponding condensation products which can be reduced using hydrogenation or transferhydrogenation conditions. This one-pot procedure would represent a selective amination or alkylation of a methylene group.