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

在这个项目中，我们研究了后过渡金属络合物的O-H活化。结果表明，[Ir(μn-Cl)(BINAP)]2(1)能很好地活化甲醇，而甲醇的络合物1及其氧化加成络合物是以甲醇为氢源的烯烃加氢反应的有效催化剂前体。虽然这些配合物也可以作为前手性烯烃不对称加氢的催化剂前体，但它们的催化活性不够高，对脱氢氨基酸的对映体选择性仍高达50%ee。配合物1也能很容易地活化各种羧酸，在5种可能的立体异构体中，(S)-1定量地和立体选择性地给出了单核(羧基)配合物(S)-OC-6-23-A-[Ir(Cl)(H)(h^2-0_2CR){(S)-binap}](R=Me，Ar)(2)。发现配合物2是亚胺不对称氢化反应非常有效的催化剂前体。特别是对于环亚胺的氢化，在…中有很高的光学性能实现了99%以上的还原。所谓的中性双膦催化剂“RhCl(双膦)”已被原位制备并用于多种催化反应，但它的分离很少，其络合物也没有得到很好的表征。我们成功地分离和全面表征了配合物1的类似物[Rh(μ-Cl){(S)-BINAP}]_2(3)。配合物3与1具有非常相似的结构，但性质与配合物1有很大不同；配合物1对空气和质子分子非常敏感，但即使在加热条件下，配合物3对这些物质也是惰性的。由于络合物3被认为对二氢的活化有效，因此需要对络合物3进行更详细的研究。对络合物1和3进行比较研究将为它们的应用提供有用的信息。此外，我们还为A.Togni和H.Grutzmacher主编并由Wiley-VCH出版的一本书《催化异功能化》撰写了一篇关于O-H活化的评论文章。较少

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