Facile Oxidation of Sulfides to Sulfoxides using Sodium Hypochlorite and Oxoammonium Salt as a Catalyst: Chemo- and Diastereoselective Transformation of Bis(phenylthio)alkanes into Sulfoxides
摘要:
本文介绍了一种简便且具有选择性的方法来进行上述转化。在 TEMPO 的介导以及溴化钾和四氯化碳的共同催化下,二硫化物与一或两个当量的次氯酸钠发生两相氧化反应,分别生成相应的一硫醚或二硫醚。在 1,2- 1,3-双(苯硫基)烷烃和正交双(苯硫基甲基)苯的情况下,可生成相应的中二硫醚,非对映选择性为 90-98%。
Allylic C−H Amination for the Preparation of syn-1,3-Amino Alcohol Motifs
摘要:
A highly selective and general Pd/sulfoxide-catalyzed allylic C-H amination reaction en route to syn-1,3-amino alcohol motifs is reported. Key to achieving this reactivity under mild conditions is the use of electron-deficient N-nosyl carbamate nucleophiles that are thought to promote functionalization by furnishing higher concentrations of anionic species in situ. The reaction is shown to be orthogonal to classical C-C bond-forming/-reduction sequences as well as nitrene-based C-H amination methods.
Catalytic Enantioselective Oxidation of Bulky Alkyl Aryl Thioethers with H2O2 over Titanium-Salan Catalysts
作者:Konstantin P. Bryliakov、Evgenii P. Talsi
DOI:10.1002/ejoc.201100557
日期:2011.8
procedure for the oxidation of bulky (preferably aryl benzyl substituted) thioethers with hydrogen peroxide in good to high yields and enantioselectivities (up to 98.5 % ee) is reported. The high optical yields are achieved in a tandem stereoconvergent enantioselective oxidation and kinetic resolution process. A reasonable balance between the sulfoxide yield and enantioselectivity could be found by varying
Sulfoxide ligand metal catalyzed oxidation of olefins
申请人:The Board of Trustees of the University of Illinois
公开号:US10266503B1
公开(公告)日:2019-04-23
The enantioselective synthesis of isochroman motifs has been accomplished via Pd(II)-catalyzed allylic C—H oxidation from terminal olefin precursors. Critical to the success of this goal was the development and utilization of a novel chiral aryl sulfoxide-oxazoline (ArSOX) ligand. The allylic C—H oxidation reaction proceeds with the broadest scope and highest levels asymmetric induction reported to date (avg. 92% ee, 13 examples ≥90% ee). Additionally, C(sp3)-N fragment coupling reaction between abundant terminal olefins and N-triflyl protected aliphatic and aromatic amines via Pd(II)/sulfoxide (SOX) catalyzed intermolecular allylic C—H amination is disclosed. A range of 52 allylic amines are furnished in good yields (avg. 76%) and excellent regio- and stereoselectivity (avg. >20:1 linear:branched, >20:1 E:Z). For the first time, a variety of singly activated aromatic and aliphatic nitrogen nucleophiles, including ones with stereochemical elements, can be used in fragment coupling stiochiometries for intermolecular C—H amination reactions.
Serial Ligand Catalysis: A Highly Selective Allylic C−H Oxidation
作者:Mark S. Chen、Prabagaran Narayanasamy、Nathan A. Labenz、M. Christina White
DOI:10.1021/ja0500198
日期:2005.5.18
We are reporting a mild, chemo-, and highly regioselective Pd(II)-catalyzed allylicoxidation of alpha-olefins to furnish branched allylic esters that proceeds via a novel serial ligand catalysis mechanism in which two different ligands (i.e., vinyl sulfoxide 2 and BQ) interact sequentially with the metal to promote distinct steps of the catalytic cycle (i.e., C-H cleavage and pi-allyl functionalization
Synthesis of C3- and C2-symmetric tris- and bis-sulfoxide ligands by asymmetric oxidation
作者:Peter K. Dornan、Priscilla L. Leung、Vy M. Dong
DOI:10.1016/j.tet.2011.02.023
日期:2011.6
A series of tris- and bis-sulfoxides were synthesized by multiple asymmetric oxidation of the corresponding sulfides. High enantioselectivities were obtained based on Horeau-type amplification of selectivity. Naphthyl-substituted sulfoxides allowed for higher selectivity and greater ease of purification. These sulfoxides were tested as ligands in rhodium-catalyzed olefin hydroacylation and 1,4-addition of phenyl boronic acid to 2-cyclohexen-1-one. While no enantioinduction was observed in hydroacylation, up to 80% ee was obtained for a tris-sulfoxide and a bis-sulfoxide ligand in the 1,4-addition. Bis-sulfoxides with flexible backbones gave lower and inversed enantioselectivity, suggesting backbone rigidity plays a key role in enantioinduction. (C) 2011 Elsevier Ltd. All rights reserved.
Vanadium catalyzed enantioselective oxidation of sulfides: easy transformation of bis(arylthio)alkanes into C2 symmetric chiral sulfoxides
A facile and selective method for the title transformation is described. The two-phase oxidation of bis-sulfides with hydrogen peroxide catalyzed by vanadium complex of chiral Schiff base leads to the corresponding chiral mono- and bis-sulfoxides. In the case of 1,2-bis(arylthio)ethanes the respective optically active bis-sulfoxides are formed in up to over 95% e.e. (C) 1999 Elsevier Science Ltd. All rights reserved.