Abstract A spiro bisphosphine oxide (SpinPO) was found to be an efficient chiral Lewis base catalyst in asymmetric reductive aldol reaction of enones and aldehydes in the presence of trichlorosilane as the reductant, affording a variety of β-hydroxyketones in good yields with moderate to high levels of diastereo- and enantioselectivities.
Two new chiral diphenylphosphine dioxides bearing an original bis(triazolyl) backbone were prepared through a two‐step sequence. The key reactioninvolves a copper‐catalyzed [3+2] cycloaddition/dimerization reaction leading to the formation of five bonds in one chemical step with 100 % atom efficiency. Interestingly, these ligands exhibited good to excellent catalytic activities as chiral Lewis base
Tailored trisubstituted chiral Cp<sup>x</sup>Rh<sup>III</sup> catalysts for kinetic resolutions of phosphinic amides
作者:Y. Sun、N. Cramer
DOI:10.1039/c7sc05411d
日期:——
position of the Cp ring leads to substantially increased selectivities for rhodium(III)-catalyzed kinetic resolutions and allowed for s-factors of up to 50. Their superiority is demonstrated by kinetic resolutions of phosphinic amides providing access to compounds with stereogenicphosphorus(V) atoms. The unreacted acyclic phosphinic amide and the cyclized product are both obtained in good yields and
引入了三取代的手性Cp x配体家族。基于双取代的惰性手性Cp x配体支架,在Cp环的中心位置引入庞大的第三取代基会导致铑(III)催化的动力学拆分的选择性大大提高,并允许s因子高达50。次膦酰胺的动力学拆分证明了它们的优越性,次膦酸酯提供了获取具有立体性磷(V)原子的化合物的途径。未反应的无环次膦酰胺和环化产物均以良好的收率和对映选择性获得。配体合成利用了后期修饰并扩展了可及的配体Cp x 配体组合。
Asymmetric Synthesis of <i>P</i>-Stereogenic Compounds via Thulium(III)-Catalyzed Desymmetrization of Dialkynylphosphine Oxides
Z/E ratios and enantioselectivities (up to >95/5 Z/E and 97% ee), which could be transformed into versatile optically active phosphine oxide derivatives. X-ray single crystalstructures of chiral N,N′-dioxides with rare-earth metal triflates revealed how the metal center and ligand structure affect the enantioselectivity.
已开发了手性th(III)催化的二炔基膦氧化物的硫共轭加成反应,以构建P-立体异构中心。在反应条件下,在炔烃末端位置具有芳基,烷基,烯基取代基的二炔基膦氧化物是可容许的。以中等至良好的收率(高达92%的收率)获得了具有较高Z / E比和对映选择性(高达> 95/5 Z / E和97%ee)的相应含P,S化合物,可以对其进行转化成为通用的光学活性氧化膦衍生物。手性N,N'的X射线单晶结构-二氧化物与稀土金属三氟甲磺酸盐显示了金属中心和配体结构如何影响对映选择性。