IF<sub>5</sub> affects the final stage of the Cl–F exchange fluorination in the synthesis of pentafluoro-λ<sup>6</sup>-sulfanyl-pyridines, pyrimidines and benzenes with electron-withdrawing substituents
A difficult chlorine–fluorine (Cl–F) exchange fluorination reaction in the final stage of the preparation of pentafluoro-λ6-sulfanyl-(hetero)arenes having electron-withdrawing substituents has now been elucidated through the use of iodinepentafluoride. A major side-reaction of C–S bond cleavage was sufficiently inhibited by the potential interaction between F and I with a halogen bonding.
A novel strategy for the synthesis of arylsulfur pentafluorides by silver carbonate-induced Cl–F exchange fluorination of arylsulfur chlorotetrafluorides is reported. This fluorination does not require any exogenous fluoride sources. Rather, the reaction proceeds via the self-immolation of the substrate Ar-SF4Cl.
Novel strategies for the synthesis of unsymmetrical glycosyl disulfides
作者:Goreti Ribeiro Morais、Bradley R. Springett、Martin Pauze、Lisa Schröder、Matthew Northrop、Robert A. Falconer
DOI:10.1039/c6ob00230g
日期:——
Novel strategies for the efficient synthesis of unsymmetrical glycosyl disulfides are reported. Glycosyl disulfides are increasingly important as glycomimetics and molecular probes in glycobiology. Sialosyl disulfides are synthesised directly from the chlorosialoside Neu5Ac2Cl, proceeding via a thiol-disulfide exchange reaction between the sialosyl thiolate and symmetrical disulfides. This methodology
Synthesis and Characterization of 2‐Pyridylsulfur Pentafluorides
作者:Oleksandr S. Kanishchev、William R. Dolbier
DOI:10.1002/anie.201409990
日期:2015.1.2
group. Herein we report that excess oxidative fluorination of 2,2′‐dipyridyl disulfide with a KF/Cl2/MeCN system leads to the formation of thirteen new 2‐pyridylsulfur chlorotetrafluorides (2‐SF4Cl‐pyridines). These molecules are found to undergo further chlorine–fluorine exchange reactions by treatment with silver(I) fluoride enabling ready access to a series of ten new substituted 2‐pyridylsulfur pentafluorides