sulfonium การใช้

• In addition, the dialkylsulfide by-products from sulfonium reagents.
• This colourless salt consists of a sulfonium cation and the triflate anion.
• In this reaction, a sulfonium is the leaving group instead of chloride.
• Some azo dyes are modified with sulfonium groups to give them a positive charge.
• In the Johnson Corey Chaykovsky reaction epoxides are generated from carbonyl groups and sulfonium ylides.
• It is the simplest sulfonium cation.
• The effect is seen in certain amines, phosphines, sulfonium and oxonium ions, sulfoxides, and even carbanions.
• Even neutral nucleophiles can be used due to the highly electrophilic nature of the sulfonium . for example, the electron-rich aromatic ring of veratrole:
• Ylides are regarded as positively charged heteroatoms connected to negatively charged carbon atoms, which include ylides of sulfonium, thiocarbonyl, oxonium, nitrogen, and carbonyl.
• These reactions use Umemoto's reagent, a sulfonium salt that serves as an electrophilic source of the trifluoromethyl group and that is precedented to react via a single-electron transfer pathway.
• For example, in Swern oxidation, the formation of sulfonium chloride must be performed in a cooled system (  30 癈 ), because at room temperature the reaction undergoes explosive thermal runaway.
• Other carbon acids susceptible to deprotonation by NaH include sulfonium salts and DMSO . NaH is used to make sulfur ylides, which in turn are used to convert ketones into epoxides, as in the Johnson Corey Chaykovsky reaction.
• Initial addition of the ylide results in a betaine with adjacent charges; density functional theory calculations have shown that the rate-limiting step is rotation of the central bond into the conformer necessary for backside attack on the sulfonium.
• Variations include another CF 3 donor " potassium ( trifluoromethyl ) trimethoxyborate ", the use of aryl boronic acids or the use of a trifluoromethyl sulfonium salt or the use of a trifluoromethylcopper ( I ) phenanthroline complex.
• Use of a sulfoxonium allows more facile preparation of the reagent using weaker bases as compared to sulfonium ylides . ( The difference being that a sulfoxonium contains a doubly bonded oxygen whereas the sulfonium does not . ) The former react slower due to their increased stability.
• Use of a sulfoxonium allows more facile preparation of the reagent using weaker bases as compared to sulfonium ylides . ( The difference being that a sulfoxonium contains a doubly bonded oxygen whereas the sulfonium does not . ) The former react slower due to their increased stability.