437613-72-4Relevant academic research and scientific papers
Recyclable chiral metathesis catalysts
-
Page 9, (2010/02/05)
The present invention relates to chiral metal catalysts for stereoselective olefin metathesis reactions, which are recyclable and reusable in such metathesis reactions. The chiral metal-based metathesis catalysts of the invention comprise multidentate optically active or racemic chiral ligands that enable their use in asymmetric synthetic processes, such as for example, in ring-opening and ring-closing metathesis reactions (ROM and RCM, respectively) of alkenes. The catalysts of the invention are organometallic complexes of multivalent metals comprising one or more chiral bidentate ligands that exhibit superior reactivity and stereoselectivity properties. The present invention also provides methods of making such catalysts and methods for utilizing them in catalyzing stereoselective olefin metathesis reactions to provide asymmetric products in relatively high enantiomeric or stereoisomeric excess.
A recyclable chiral RU catalyst for enantioselective olefin metathesis. Efficient catalytic asymmetric ring-opening/cross metathesis in air
Van Veldhuizen, Joshua J.,Garber, Steven B.,Kingsbury, Jason S.,Hoveyda, Amir H.
, p. 4954 - 4955 (2007/10/03)
The synthesis and structure of a new chiral bidentate imidazolinylidene ligand and a derived chiral Ru-based carbene are disclosed. The Ru complex is stereogenic at the metal center; it can be prepared in >98% diastereoselectivity and purified by silica gel chromatography with undistilled solvents. The air-stable Ru complex efficiently catalyzes ring-closing and ring-opening metathesis and is recyclable. The chiral complex is highly effective (0.5-10 mol % loading) in promoting enantioselective ring-opening/cross metathesis reactions (up to >98% ee). These enantioselective transformations can be effected in air, with unpurified solvent and with substrates that would only polymerize with Mo-based catalysts. Copyright
