93222-01-6Relevant academic research and scientific papers
Stereoselective Rh-Catalyzed Hydrogenative Desymmetrization of Achiral Substituted 1,4-Dienes
Fernández-Pérez, Héctor,Lao, Joan R.,Vidal-Ferran, Anton
supporting information, p. 2836 - 2839 (2016/07/06)
Highly efficient catalytic stereoselective hydrogenative desymmetrization reactions mediated by rhodium complexes derived from enantiopure phosphine-phosphite (P-OP) ligands are described. The highest performing ligand, which contains a TADDOL-derived phosphite fragment [TADDOL = (2,2-dimethyl-1,3-dioxolane-4,5-diyl)bis(diphenylmethanol)], presented excellent catalytic properties for the desymmetrization of a set of achiral 1,4-dienes, providing access to the selective formation of a variety of enantioenriched secondary and tertiary alcohols (six examples, up to 92% ee).
Stereoselectivity in the rhodium-catalysed reductions of nonconjugated dienes
Nguyen, Bao,Brown, John M.
supporting information; scheme or table, p. 1333 - 1343 (2009/12/27)
The stereochemical course of rhodium-catalysed addition of hydrogen and catecholborane to bicyclo[2.2.1]heptadiene, and of hydrogen to a range of cyclic dienes has been analysed. For hydroboration, the overall catalytic reaction possesses exo-selectivity, but the initial step is endo-selective. For hydrogenation (deuteration), the first step may occur with either exo- or endo- selectivity, depending on the structure of the diene. This enables a distinction to be made between pathways involving prior dissociation of the diene, and direct addition to the complexed diene without full dissociation. The relative ease of hydrogenation of the first and second doublebonds varies markedly with reactant structure, and also depends on the choice of catalyst ligands. For dicyclopentadiene, hydrogenation of the cyclopentene double bond is accompanied by rapid alkene isomerisation, as revealed by deuterium addition. The asymmetric hydrogenation of acyclic skipped mesodienes is reported, demonstrating control of relative rates of the two sequential steps, with ees of up to 53% after the first reduction.
Mechanistic implications of nickel-catalyzed reductive coupling of aldehydes and chiral 1,6-enynes
Moslin, Ryan M.,Jamison, Timothy F.
, p. 455 - 458 (2007/10/03)
A study of nickel-catalyzed reductive coupling reactions of aldehydes and chiral 1,6-enynes has provided evidence for three distinct mechanistic pathways that govern regioselectivity in this transformation. In the absence of a phosphine additive, high regioselectivity and high diastereoselectivity are obtained as a direct result of coordination of both the alkyne and the olefin to the metal center during the C-C bond-forming step.
Directing effects of tethered alkenes in nickel-catalyzed coupling reactions of 1,6-enynes and aldehydes
Moslin, Ryan M.,Miller, Karen M.,Jamison, Timothy F.
, p. 7598 - 7610 (2007/10/03)
Nickel-catalyzed reductive coupling reactions of aldehydes and 1,6-enynes proceed in excellent regioselectivity in the absence of a phosphine, and the use of a monodentate phosphine additive leads to the formation of the opposite regioisomer with equally high selectivity. Both products are the result of the same fundamental mechanism, with the inversion of regioselectivity being the result of stereospecific ligand substitution at the metal center.
An Efficiente Preperation of Optically Active Allylic Alcohols, 2-Furyl Alcohols and 2-Thienyl Alcohols by Catalytic Asymmetric Alkylation
Hayashi, Masahiko,Kaneko, Toshiyuki,Oguni, Nobuki
, p. 25 - 28 (2007/10/02)
Highly enantioselective alkylation of some kinds of α,β-unsaturated aldehydes with dialkylzinc proceed in the presence of a small amount of a chiral β-amino alcohol, thus providing an efficient method of obtaining optically active secondary allylic alcohols.Optically active 2-furyl and 2-thienyl alcohols are also available by this catalytic asymmetric alkylation method.
