Electrolytic Partial Fluorination of Organic Compounds.71.1 Highly Diastereoselective Anodic Fluorination of Sulfides Having Oxygen-Containing Heterocyclic Groups
摘要:
Diastereoselective anodic fluorination of sulfides having various oxygen-containing heterocyclic substituents such as 2-furanyl, 1,3-dioxolanyl, 2,2-dimethyl-1,3-dioxolanyl, 2-spirocyclohexyl-1,3-dioxolanyl, 2-spiroadamantyl-1,3-dixolanyl, and 1,3-dioxolanonyl groups at the beta-position was comparatively studied. Among the oxygen-containing heterocyclic substituents, the 2-spirocyclohexyl-1,3-dioxolanyl group gave the best diastereoselectivity (80% de). The diastereoselectivity was also affected by supporting fluoride salts and solvents. Chemical fluorination using selectfluor resulted in much lower diastereoselectivity and extremely poor yield. The fluorinated products were readily converted into the corresponding fluorinated diol in good yields by acidic hydrolysis.
Merging shuttle reactions and paired electrolysis for reversible vicinal dihalogenations
作者:Xichang Dong、Johannes L. Roeckl、Siegfried R. Waldvogel、Bill Morandi
DOI:10.1126/science.abf2974
日期:2021.1.29
shuttle (e-shuttle) paradigm for the facile and scalable interconversion of alkenes and vicinal dihalides, a class of reactions that can be used both to synthesize useful dihalogenated molecules from simple alkenes and to recycle waste material through retro-dihalogenation. The reaction is demonstrated using 1,2-dibromoethane, as well as 1,1,1,2-tetrachloroethane or 1,2-dichloroethane, to dibrominate or
Deep Eutectic Solvents as Reaction Media for the Palladium-Catalysed C−S Bond Formation: Scope and Mechanistic Studies
作者:Xavier Marset、Gabriela Guillena、Diego J. Ramón
DOI:10.1002/chem.201702892
日期:2017.8.4
system based on deep eutectic solvents and palladium nanoparticles where C−S bonds are formed from aryl boronic acids and sodium metabisulfite, is introduced. The functionalization step is compatible with a broad spectrum of reagents such as nucleophiles, electrophiles or radical scavengers. This versatile approach allows the formation of different types of products in an environmentally friendly medium
A new copper-catalyzed oxysulfenylation reaction of enolates with sodium sulfinates has been disclosed. A series of sulfenylated heterocycles including four- and seven-membered cyclic ether were obtained in mild to good yields. This reaction is proposed to go through a radical process, and the sulfur radical (RS•) may be a reactive species.
Phenylsulfenyl chloride/N,N-diisopropylethylamine: A useful reagent for cyclic ether formation (sulfenyletherification)
作者:Sudersan M Tuladhar、Alex G Fallis
DOI:10.1016/s0040-4039(00)95772-1
日期:1987.1
A general method for the formation of cyclicethers and lactones is described. The procedure employs phenylsulfenyl chloride and N,N-diisopropylethylamine to generate an episulfonium ion intermediate from which the cyclic products arise by internal nucleophilic displacement.
Evolution of a Polyene Cyclization Cascade for the Total Synthesis of (−)-Cyclosmenospongine
作者:Klaus Speck、Thomas Magauer
DOI:10.1002/chem.201605029
日期:2017.1.23
We report a full account on the development of a unique cationic polyenecyclization for the total synthesis of the tetracyclic meroterpenoid (−)‐cyclosmenospongine. A highly convergent three‐component coupling strategy enabled rapid access to individual cyclization precursors that were tested for their reactivity. The successful transformation generates three rings and sets four consecutive stereocenters