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- Silica-immobilized chiral dirhodium(II) catalyst for enantioselective carbenoid reactions.
Silica-immobilized chiral dirhodium(II) catalyst for enantioselective carbenoid reactions.
Organic letters (2013-11-21)
Kathryn M Chepiga, Yan Feng, Nicholas A Brunelli, Christopher W Jones, Huw M L Davies
PMID24251986
ABSTRACT
A silica-supported dirhodium(II) tetraprolinate catalyst was synthesized in four steps from l-proline and used in a range of enantioselective transformations of donor/acceptor carbenoids. These include cyclopropenation, cyclopropanation, tandem ylide formation/[2,3] sigmatropic rearrangement, and a variety of combined C-H functionalization/Cope rearrangement reactions. The products of these transformations were obtained in yields and levels of enantioselectivity comparable to those obtained with its homogeneous counterpart, Rh2(S-DOSP)4. The silica-supported Rh2(S-DOSP)4 derivative was successfully recycled over five reactions.
MATERIALS
Product Number
Brand
Product Description
Sigma-Aldrich
Silica, nanopowder, spec. surface area 175-225 m2/g (BET), 99.8% trace metals basis
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Silicon dioxide, nanopowder (spherical, porous), 5-20 nm particle size (TEM), 99.5% trace metals basis
Sigma-Aldrich
Silicon dioxide, nanopowder, 10-20 nm particle size (BET), 99.5% trace metals basis