Electrolytic Partial Fluorination of Organic Compounds. 17. Regiospecific Anodic Fluorination of Sulfides Bearing Electron-Withdrawing Substituents at the Position .alpha. to the Sulfur Atom
摘要:
Regiospecific monofluorination of various sulfides bearing electron-withdrawing substituents, cyano, ester, acyl, amino, and phosphonate groups,at their alpha-positions was successfully carried out by the anodic oxidation of the sulfides in Et(3)N . 3HF/MeCN using an undivided cell. Fluorine was introduced at the position alpha to the sulfur atom selectively. Fluorination of alpha-(phenylthio)-substituted cyclic carbonyl compounds was also successful. Furthermore, anodic alpha,alpha-difluorination of ethyl alpha-(phenylthio)acetate was also successfully carried out although a large amount of electricity was required.
[EN] MYOGLOBIN-BASED CATALYSTS FOR CARBENE TRANSFER REACTIONS<br/>[FR] CATALYSEURS À BASE DE MYOGLOBINE POUR RÉACTIONS DE TRANSFERT DE CARBÈNE
申请人:UNIV ROCHESTER
公开号:WO2016086015A1
公开(公告)日:2016-06-02
Methods are provided for carrying out carbene transfer transformations such as olefin cyclopropanation reactions, carbene heteroatom-H insertion reactions (heteroatom = N, S, Si), sigmatropic rearrangement reactions, and aldehyde olefination reactions with high efficiency and selectivity by using a novel class of myoglobin-based biocatalysts. These methods are useful for the synthesis of a variety of organic compounds which contain one or more new carbon-carbon or carbon-heteroatom (N, S, or Si) bond. The methods can be applied for conducting these transformations in vitro (i.e., using the biocatalyst in isolated form) and in vivo (i.e., using the biocatalyst in a whole cell system).
Intermolecular carbene S–H insertion catalysed by engineered myoglobin-based catalysts
作者:Vikas Tyagi、Rachel B. Bonn、Rudi Fasan
DOI:10.1039/c5sc00080g
日期:——
The first example of a biocatalytic strategy for the synthesis of thioethers via an intermolecular carbene S–H insertion reaction is reported. Engineered variants of sperm whale myoglobin were found to efficiently catalyze this C–S bond forming transformation across a diverse set of aryl and alkyl mercaptan substrates and α-diazoester carbene donors, providing high conversions (60–99%) and high numbers
In the field of chiralBrønstedbase catalysis, a new generation of chiralcatalysts has been highly anticipated to overcome the intrinsic limitation of pronucleophiles that are applicable to the enantioselective reactions. Herein, we reveal conceptually new chiralBrønstedbasecatalysts consisting of two different organobase functionalities, one of which functions as an organosuperbase and the other
Simple, economical and environmentally friendly sulfone synthesis
作者:Diego A. Alonso、Carmen Nájera、Montserrat Varea
DOI:10.1016/s0040-4039(02)00598-1
日期:2002.5
Chemoselective sulfur oxidation of functionalized sulfides was developed using catalytic amounts of MnSO4·H2O (1 mol%) and 30% H2O2 in the presence of a buffer solution of NaHCO3. Aromatic and aliphatic sulfides were oxidized to sulfones in quantitative yields in 15 min. Different functional groups including double bonds, alcohols, ethers of THP and TBDMS groups were tolerated under these mild and
在NaHCO 3缓冲溶液的存在下,使用催化量的MnSO 4 ·H 2 O(1 mol%)和30%H 2 O 2进行了官能化硫化物的化学选择性硫氧化反应。在15分钟内以定量收率将芳香族和脂肪族硫化物氧化为砜。在这些温和和绿色的反应条件下,可以耐受不同的官能团,包括双键,醇,THP和TBDMS基团的醚。
Cu(I)/Chiral Bisoxazoline-Catalyzed Enantioselective Sommelet–Hauser Rearrangement of Sulfonium Ylides
作者:Shu-Sen Li、Jianbo Wang
DOI:10.1021/acs.joc.0c01590
日期:2020.10.2
asymmetric thia-Sommelet–Hauser rearrangement of sulfonium ylides remains a great challenge due to its multistep reaction mechanism involving metal carbene formation, proton transfer, and [2,3]-sigmatropic rearrangement. In particular, the key problem of such reactions is the differentiation of the enantiotopic lone pair electrons of sulfur, which generates the sulfonium ylide intermediate bearing chirality