The Morita‐Baylis–Hillman (MBH) reaction and [3, 3]‐sigmatropic rearrangement are two paradigms in organic synthesis. We have merged the two types of reactions to achieve [3,3]‐rearrangement of arylsulfoxides with α,β‐unsaturated nitriles. The reaction was achieved by sequentially treating both coupling partners with electrophilic activator (Tf2O) and base, offering an effective approach to prepare
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
Aromatic [5,5]‐sigmatropic rearrangement is an appealing protocol for accessing 1,4‐substituted arenes. However, such a protocol has not been well utilized in organicsynthesis because of the difficulties in the synthesis of the substrates, selectivity issues, and limited substrate scope. Described herein is a new [5,5]‐sigmatropic reaction utilizing readily available aryl sulfoxides and allyl nitriles
芳香族[5,5] -sigmatropic重排是一种吸引人的协议,可用于访问1,4-取代的芳烃。但是,由于底物的合成困难,选择性问题以及底物范围有限,这种方案在有机合成中并未得到很好的利用。本文描述的是一种新的[5,5]-σ反应,利用易获得的芳基亚砜和烯丙基腈。该反应具有温和的反应条件,高的化学和区域选择性,出色的官能团相容性以及广泛的底物范围。计算研究表明,反应的成功可归因于重排前体的选择性亲电组装,其中线性-C = C = N-键比竞争性[3,3]更有利于[5,5]-σ重排。 ]-σ重排。
Desymmetrization of Prochiral Diaryl Sulfoxides by an Asymmetric Sulfoxide-Magnesium Exchange
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).