The aryneinsertion into “S═O” bond has been validated recently. This technology is elusively applied to the synthesis of thioethers. In contrast to the reported cases, the reaction described furnished o-aryloxy triarylsulfonium salts, in lieu of thioethers, in good to excellent yields. The reaction is also featured by its exquisite regioselectivity, broad substrate scope, and mild conditions (25 °C)
Asymmetric Sulfinylations of<i>N</i>-Methylephedrine-Modified Tri- or Tetraalkyl Zincates by Symmetric Diaryl Sulfoxides
作者:Simon Ruppenthal、Reinhard Brückner
DOI:10.1002/ejoc.201701603
日期:2018.6.7
Diethylzinc was treated with 1 or 2 equiv. of AlkMgCl or PhMgBr (preferably) or with 1 equiv. of nBuLi (less efficiently) for forming species – plausibly zincates – which were sulfinylated by diaryl sulfoxides to give racemic alkyl aryl sulfoxides in yields reaching 100 %. Dialkylzinc reagents were also activated by treatments with 1 or 2 equiv. of an enantiomericallypure alkylmagnesium β‐aminoalkoxide
Reactions between arynes and alkyl sulfides have been extensively studied over the past few decades. These reactions commonly end with a dealkylation process and thus deliver thioethers as final products. In contrast, the transformation described furnishes valuable triarylsulfonium salts, in lieu of thioethers, from arynes and diarylsulfides. The reaction features mild conditions and a broad substrate
The first desymmetrizations of prochiraldiarylsulfoxides 1 by an asymmetricsulfoxide–magnesiumexchange reaction are reported. The respective substrate (1), iPr2Mg, and the dilithium salt of (S)‐BINOL (which was prepared in situ) provided (S)‐configured aryl isopropyl sulfoxides 2 in up to 91 % yield and with up to 91 % ee. (S)‐BINOL was re‐isolable in 98 % yield.
Symmetric Diarylsulfoxides as Asymmetric Sulfinylating Reagents for Dialkylmagnesium Compounds
作者:Simon Ruppenthal、Reinhard Brückner
DOI:10.1021/jo502417j
日期:2015.1.16
dilithium salt of (S)-BINOL was added as a promotor. Alkyl aryl sulfoxides resulted in up to quantitative yield and with up to 97% ee. This demonstrates the feasibility of asymmetric sulfinylations by achiral sulfinylating agents (from the perspective of Alkyl2Mg) as well as the feasibility of asymmetricsulfoxide–magnesiumexchanges (from the perspective of Ar2SO).