作者:Xiaofeng Wu、Xiaohong Li、Antonio Zanotti-Gerosa、Allan Pettman、Jianke Liu、Allan James Mills、Jianliang Xiao
DOI:10.1002/chem.200701258
日期:2008.2.27
formate in neat water is shown to be viable with Rh-TsDPEN and Ir-TsDPEN catalysts, derived in situ from [Cp*MCl2]2 (M=Rh, Ir) and TsDPEN. A variety of ketones were reduced, including nonfunctionalized aryl ketones, heteroaryl ketones, ketoesters, and unsaturated ketones. In comparison with Ir-TsDPEN and the related Ru II catalyst, the Rh III catalyst is most efficient in water, affording enantioselectivities
研究表明,纯净水中甲酸酯在酮中的不对称转移氢化(ATH)在Rh-TsDPEN和Ir-TsDPEN催化剂上是可行的,该催化剂原位衍生自[Cp * MCl2] 2(M = Rh,Ir)和TsDPEN。还原了多种酮,包括未官能化的芳基酮,杂芳基酮,酮酸酯和不饱和酮。与Ir-TsDPEN和相关的Ru II催化剂相比,Rh III催化剂在水中的效率最高,即使在100-1000的底物/催化剂(S / C)比下,对映选择性高达99%ee。惰性气氛。水相还原显示出高度依赖pH值;对于Rh-和Ir-TsDPEN,TOF大于50 mol mol(-1)h(-1)的最佳pH窗口分别为5.5-10.0和6.5-8.5。在pH窗口之外,根据pH的不同,还原速度会变慢或停滞。但是,对映选择性仅在酸性条件下会腐蚀。在较高的S / C比下,Rh-TsDPEN的ATH水溶液显示出对产物以及副产物的抑制作用。产物抑制似乎至少