159652-77-4Relevant academic research and scientific papers
Stereospecific consecutive epoxide ring expansion with dimethylsulfoxonium methylide
Butova, Ekaterina D.,Barabash, Anastasiya V.,Petrova, Anna A.,Kleiner, Christian M.,Schreiner, Peter R.,Fokin, Andrey A.
experimental part, p. 6229 - 6235 (2010/11/18)
Figure presented. Consecutive ring-expansion reactions of oxiranes with dimethylsulfxonium methylide were studied experimentally and modeled computationally at the density functional theory (DFT) and second-order Moller-Plesset (MP2) levels of theory utilizing a polarizable continuum model (PCM) to account for solvent effects. While the epoxide to oxetane ring expansion requires 13-17 kcal mol-1 activation and occurs at elevated temperatures, the barriers for the ring expansions to oxolanes are higher (ca. 25 kcal mol-1) and require heating to 125 °C. Further expansions of these oxolanes to the six-membered oxanes are hampered by high barriers (ca. 40 kcal mol-1). We observe the complete conservation of the enantiomeric purities for the nucleophilic ring expansions of enantiomeric 2-mono- and 2,2-disubstituted epoxides and oxetanes with dimethylsulfoxonium methylide. This is a convenient general approach for the high-yielding preparation of optically active four- and five-membered cyclic ethers from oxiranes.
Asymmetric Synthesis of 2-Aryl Substituted Oxetanes by Enantioselective Reduction of β-Halogenoketones using Lithium Borohydride modified with N,N'-Dibenzoylcystine
Soai, Kenso,Niwa, Seiji,Yamanoi, Takashi,Hikima, Hitoshi,Ishizaki, Miyuki
, p. 1018 - 1019 (2007/10/02)
Optically active 2-aryl substituted oxetanes are synthesised in high enantiomeric excesses (up to 89percent e.e.) via enantioselective reduction of β-halogenoketones with lithium borohydride using (R,R')-N,N'-dibenzoylcystine and t-butyl alcohols as ligands.
