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A manganese catalyst of a facially coordinating P,N,N ligand catalyses the hydrogenation of imines derived from indanone derivatives with high enantioselectivity. There is no requirement for an activating group and imines can be generated in situ. The selectivity can be rationalised by DFT calculations. [ABSTRACT FROM AUTHOR]

The scope of carbon monoxide‐free Asymmetric Transfer HydroFormylation (ATHF) procedures using a highly active single catalyst system derived from 1,2‐bis‐((2,5)‐diphenylphospholano)ethane as chiral ligand has been studied. This reveals some highly successful reactions, but also significant limitations. The development of a new protocol in which a catalyst for formaldehyde decomposition to CO and H2 is combined with the catalyst of choice for the subsequent asymmetric hydroformylation is described. This enables ATHF reactions that were problematic to be significantly improved. The new method has been used in the synthesis of several key precursors to biologically active molecules. [ABSTRACT FROM AUTHOR]

Enantioselective hydrogenation of ketones is a key reaction in organic chemistry. In the past, we have attempted to deal with some unsolved challenges in this arena by introducing chiral tridentate phosphine-diamine/Ru catalysts. New catalysts and new applications are presented here, including the synthesis of phosphine-amino-alcohol P,N,OH ligands derived from (R,S)-1-amino-2-indanol, (S,S)-1-amino-2-indanol and a new chiral P,N,N ligand derived from (R, R)-1,2-diphenylethylenediamine. Ruthenium pre-catalysts of type [RuCl2(L)(DMSO)] were isolated and then examined in the hydrogenation of ketones. While the new P,N,OH ligand based catalysts are poor, the new P,N,N system gives up to 98% e.e. on substrates that do not react at all with most catalysts. A preliminary attempt at realising a new delta lactone synthesis by organocatalytic Michael addition between acetophenone and acrylonitrile, followed by asymmetric hydrogenation of the nitrile functionalised ketone is challenging in part due to the Michael addition chemistry, but also since Noyori pressure hydrogenation catalysts gave massively reduced reactivity relative to their performance for other acetophenone derivatives. The Ru phosphine-diamine system allowed quantitative conversion and around 50% e.e. The product can be converted into a delta lactone by treatment with KOH with complete retention of enantiomeric excess. This approach potentially offers access to this class of chiral molecules in three steps from the extremely cheap building blocks acrylonitrile and methyl-ketones; we encourage researchers to improve on our efforts in this potentially useful but currently flawed process. [ABSTRACT FROM AUTHOR]

Asymmetric hydrogenation of dibenzoyl-difluoro�methane has been studied for the first time. In contrast to �BINAL-H, baker’s yeast and CBS reduction procedures, ruthenium-catalysed hydrogenation using axially chiral diphosphine ligands provides excellent yield, diastereoselectivity and good enantioselectivity (up to 72% ee). Enantiomer enrichment by recrystallisation allows for the pure fluorinated diol to be isolated as a single enantiomer in moderate yield. [ABSTRACT FROM AUTHOR]