A series of tridentate ferrocene-based amino-phosphine acid (f-Ampha) ligands have been successfully developed. The f-Ampha ligands are extremely air stable and exhibited excellent performance in the Ir-catalyzed asymmetric hydrogenation of ketones (full conversions, up to >99% ee, and 500 000 TON). DFT calculations were performed to elucidate the reaction mechanism and the importance of the -COOH group. Control experiments also revealed that the -COOH group played a key role in this reaction.
A highly chemoselective and reactive direct catalytic reduction of various amides to amines and alcohols was developed by using a tetradentate ruthenium complex. The catalytic system showed excellent activity (turnover numbers up to 19 600) and great functional group tolerance under mild reaction conditions, compared to several bidentate and tridentate ruthenium-catalyzed systems.
Whereas there is a significant interest in the rapid construction of diversely substituted saturated heterocycles, direct and modular access is currently limited to the mono-, 2,3-, or 3,4-substitution pattern. This Communication describes the straightforward and modular construction of 2,4-substituted saturated heterocycles from readily available materials in a highly stereoand regioselective manner, which sets the stage for numerous readily accessible drug motifs. The strategy relies on chain walking catalysis.
The nickel/( S)-Binapine complex was found to be an efficient catalyst for asymmetric hydrogenation of β-acetylamino vinylsulfones to afford chiral β-Amido sulfones with excellent yields and enantioselectivities (up to 95% yields and >99% ee). This protocol has good compatibility with a series of substituted ( Z)-β-acetylamino vinylsulfones or Z/ E isomeric mixtures. A gram-scale reaction has also been achieved in the presence of a 0.2 mol % catalyst loading.
While chiral allylic organophosphorus compounds are widely utilized in asymmetric catalysis and bioactive molecules, their synthetic methods are still very limited. We report the development of an asymmetric nickel/brønsted acid...
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