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Phospholane-phosphites are known to show highly unusual selectivity towards branched aldehydes in the hydroformylation of terminal alkenes. This paper describes the synthesis of hitherto unknown unsaturated phospholene borane precursors and their conversion to the corresponding phospholene-phosphites. The relative stereochemistry of one of these ligands and its Pd complex was assigned with the aid of X-ray crystal structure determinations. These ligands were able to approach the level of selectivity observed for phospholane-phosphites in the rhodium-catalysed hydroformylation of propene. High-pressure infra-red (HPIR) spectroscopic monitoring of the catalyst formation revealed that whilst the catalysts showed good thermal stability with respect to fragmentation, the C=C bond in the phospholene moiety was slowly hydrogenated in the presence of rhodium and syngas. The ability of this spectroscopic tool to detect even subtle changes in structure, remotely from the carbonyl ligands, underlines the usefulness of HPIR spectroscopy in hydroformylation catalyst development. [ABSTRACT FROM AUTHOR]

High diastereoselectivity was observed in the Rh-catalysed reductive amination of 3-arylcyclohexanones to form tertiary amines. This was incorporated into a one-pot enantioselective conjugate addition and diastereoselective reductive amination, including an example of assisted tandem catalysis. [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]

The reaction of several tertiary amine functionalised phosphines with [Pt(COD)Cl2] has been studied. Reactions with ratios of L:Pt=2 proceeded cleanly to give either cis or trans complexes depending on the cone angle of the phosphines. The trans complexes could also be prepared by reaction with Zeise''s salt. Reactions of [Pt(COD)Cl2] with L:Pt=1 are less straightforward, and a mixture of cis and trans monodentate complexes, and in one example, a chelate complex have been isolated. The X-ray crystal structures of [PtCl2(η2-iPr2PN(Me)CH2CH2NMe2)] and a monodentate complex [trans-PtCl2(η1-iPr2PNH-c-NC5H10)2] are reported. [Copyright &y& Elsevier]

Rhodium catalysed hydroformylation of unsaturated esters has been studied. A pronounced temperature dependence was observed on the regioselectivity and catalytic activity for these reactions, and under the appropriate conditions, it is possible to obtain preferentially either linear or quaternary products. A quaternary selective hydroformylation of methyl atropate to give 1,3-aldehydic esters has also been developed. [Copyright &y& Elsevier]

This method uses low catalyst loadings and is suitable for the hydrogenation of tetrasubstituted enamines. [ABSTRACT FROM AUTHOR]

The article presents chemical equations related to the article "Rhodium/Phospholane-Phosphite Catalysts Give Unusually High Regioselectivity in the Enantioselective Hydroformylation of Vinyl Arene" by G.M. Noonan and colleagues, published in the journal "Chemical Communications."

A family of novel mononuclear and dinuclear Pd-complexes of phanephos ligands, allows the highly regioselective formation of the corresponding branched isomers (III) and (VI) in the hydroxycarbonylation and methoxycarbonylation of styrene derivatives (I) and (IV). [ABSTRACT FROM AUTHOR]