38941-46-7Relevant articles and documents
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Dubois,J.E.,Bauer,P.
, p. 6993 - 6999 (1976)
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A β-Carbon elimination strategy for convenient: In situ access to cyclopentadienyl metal complexes
Smits,Audic,Wodrich,Corminboeuf,Cramer
, p. 7174 - 7179 (2017/10/05)
The electronic and steric properties of tailored cyclopentadienyl (Cp) ligands are powerful handles to modulate the catalytic properties of their metal complexes. This requires the individual preparation, purification and storage of each ligand/metal combination. Alternative, ideally in situ, complexation protocols would be of high utility. We disclose a new approach to access Cp metal complexes. Common metal precursors rapidly react with cyclopentadienyl carbinols via β-carbon eliminations to directly give the Cp-metal complexes. An advantage of this is the direct and flexible use of storable pre-ligands. No auxiliary base is required and the Cp complexes can be prepared in situ in the reaction vessel for subsequent catalytic transformations.
Asymmetric synthesis with the enzyme Coprinus peroxidase: Kinetic resolution of chiral hydroperoxides and enantioselective sulfoxidation
Adam, Waldemar,Mock-Knoblauch, Cordula,Saha-Moeller, Chantu R.
, p. 4834 - 4839 (2007/10/03)
The enzyme Coprinus peroxidase (CiP) was employed for the kinetic resolution of racemic hydroperoxides 1 and the asymmetric sulfoxidation of prochiral sulfides 4. Eleven hydroperoxides 1a-k were reduced by CiP and guaiacol as reductant under conditions of kinetic resolution with enantioselectivities of up to >98% for the (S)-hydroperoxide 1 and 90% for the (R)-alcohol 2. In the absence of a reductant, the hydroperoxide 1a afforded with CiP enantiomerically enriched hydroperoxide la (ee up to 54%) and alcohol 2a (ee up to 40%), as well as ketone 3a (which is also formed simultaneously in all other reactions) and molecular oxygen. Catalase activity was established for CiP with hydrogen peroxide. When aryl alkyl sulfides 4 were used as oxygen acceptors, three products, sulfoxides 5, alcohols 2, and hydroperoxides 1, were obtained, all in enantiomerically enriched form. The highest ee value (89%) was achieved for the sulfoxide derived from naphthyl methyl sulfide (4f). Thus, CiP may be utilized for the asymmetric synthesis of optically active hydroperoxides 1, alcohols 2, and sulfoxides 5.