164200-13-9Relevant academic research and scientific papers
Kinetic resolution of hydroperoxides with enantiopure phosphines: Preparation of enantioenriched tertiary hydroperoxides
Driver, Tom G.,Harris, Jason R.,Woerpel
, p. 3836 - 3837 (2008/02/13)
An efficient reductive kinetic resolution strategy capable of accessing optically active tertiary hydroperoxides is reported. Readily accessible tertiary hydroperoxides are resolved with commercially available (R)- or (S)-xylyl-PHANEPHOS with selectivity factors as large as 37. The resulting bis(phosphine oxide) can be recycled in high yields. The isolated mono(phosphine oxide) intermediate resolved hydroperoxides with the same selectivity as the parent bisphosphine. Copyright
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.
The titanium-catalyzed, asymmetric epoxidation of allylic alcohols with optically active hydroperoxides in the presence of achiral diol ligands
Adam, Waldemar,Korb, Marion N.
, p. 1131 - 1142 (2007/10/03)
The titanium-catalyzed, asymmetric epoxidation of dialkyl- and phenyl-substituted allylic alcohols with various enantiomerically pure hydroperoxides has been examined in the presence of achiral diol ligands. Enantioselectivities with ee values up to 50% were achieved in the oxygen transfer from (-)-(S)-1-phenylethyl 1a and (-)-(S)-1-phenylpropyl 1b hydroperoxides to 3-methyl-2-buten-1-ol 2a and geraniol 2b in the presence of the diethyl 2-hydroxy-2-hydroxymethylmalonate (DHHM) as an achiral multidentate diol ligand. The DHHM additive was ineffective in the asymmetric epoxidation of the phenyl-substituted allylic alcohols 3c-f, and only low ee values (up to 15%) were obtained. The optically active hydroperoxides (-)-(S)-1c and (-)-1d gave only moderate enantioselectivities (ee values up to 24%) with or without the achiral malonate additive DHHM. The concept of titanium-catalyzed, asymmetric epoxidation with optically active hydroperoxides as oxygen donors in the presence of multidentate diols as achiral ligands is less effective in its enantioselectivity than the Sharpless modus operandi of employing t-butyl hydroperoxide as achiral oxygen donor and the C2-symmetric tartrate as chiral auxiliary.
