Development of Practical Catalytic Asymmetric Hydrogenatioh Using Methanol as a Hydrogen Source

在这个项目中，我们研究了O-H与后过渡金属配合物的活化。我们发现[Ir(μn-Cl)(binap)]_2(1)可以很容易地活化甲醇，甲醇的配合物1及其氧化加成配合物是甲醇作为氢源的炔的高效加氢催化剂前驱体。虽然这些配合物也可以作为前手性烯烃不对称加氢的前体催化剂，但它们的催化活性不够高，对脱氢氨基酸加氢的对映选择性保持在50%左右。配合物1也能很容易地激活各种羧酸，(S)-1在5种可能的立体异构体中定量地和立体选择性地给出了单核羟基（羧酸）配合物(S)- oc -6-23- a -[Ir(Cl)(H)(H ^2- 0_2cr){(S)-binap}] (R=Me, Ar)(2)。配合物2是亚胺不对称氢化反应的有效催化剂前驱体。特别是对于环亚胺的加氢，实现了非常高的光导率，还原率超过99%。所谓中性铑-二膦催化剂“RhCl（二膦）”已被原位制备并用于多种催化，但其分离很少，络合物尚未得到很好的表征。我们已经成功地分离和充分表征了配合物1的铑类似物，[Rh(μ-Cl){(S)-binap}]_2(3)。复合体3的结构与复合体1非常相似但复合体3的性质与复合体1有很大不同；配合物1对空气和质子分子都很敏感，但配合物3即使在加热条件下对这些物质也没有反应。由于配合物3被认为对二氢的活化是有效的，因此需要对配合物3进行更详细的研究。对配合物1和3的比较研究将为它们的应用提供有用的信息。此外，我们在一本名为《催化异功能化》的书中撰写了一篇关于O-H活化的综述文章，这本书由a . Togni和H. Grutzmacher编辑，由Wiley-VCH出版。少

In this project, we studied O-H activation with late-transition metal complexes. We have found that [Ir(μn-Cl)(binap)]_2 (1) can easily activate methanol and the complex 1 and its oxidative addition complex of methanol act as efficient hydrogenation catalyst precursors of alkyne using methanol as a hydrogen source. Although these Complexes act as catalyst precursors for asymmetric hydrogenation of prochiral olefins also, their catalytic activity was not high enough and the enantio-selectivity for hydrogenation of dehydroamino acids remained as high as 50 %ee. Complex 1 can also activate various kinds of carboxylic acids very easily and (S)-1 gave quantitatively and stereoselectively, mononuclear hydrido(carboxylato) complexes (S)-OC-6-23-A-[Ir(Cl)(H)(h^2-0_2CR){(S)-binap}] (R=Me, Ar) (2), among five possible stereoisomers. Complexes 2 were found very efficient catalyst precursors for asymmetric hydrogenation of imine. Especially, for hydrogenation of cyclic imines, very high optical in … More duction over 99 %ee was realized. So-called a neutral rhodium-diphosphine catalyst, "RhCl(diphosphine)", has been prepared in situ and used in many kinds of catalysis, but its isolation is rare and the complex has not been well characterized. We have succeeded in isolation and full characterization including X-ray analysis of the rhodium analogue of complex 1, [Rh(μ-Cl){(S)-binap}]_2 (3). Complex 3 has a very similar structure to that of 1 but the properties of 3 were very much different from those of complex 1 ; Complex 1 is very sensitive against air as well as protic molecules but complex 3 was inert against these substances even at heating conditions. As complex 3 is considered to be effective for activation of dihydrogen, more detailed studies on Complex 3 will be needed. A comparative studies between complexes 1 and 3 would provide useful information about their applications. In addition, we contributed a review article about O-H activation to a book, "Catalytic Heterofunctionalization" edited by A. Togni and H. Grutzmacher and published by Wiley-VCH. Less