247129-85-7 | (2-BroMoethyl)diphenylsulfoniuM TrifluoroMethanesulfonate

CAS:247129-85-7 | (2-BroMoethyl)diphenylsulfoniuM TrifluoroMethanesulfonate,Description

(2-Bromoethyl)diphenylsulfonium trifluoromethanesulfonate is a chemical compound with potential applications in organic synthesis. It has been used as a solid precursor for in situ generation of diphenylvinylsulfonium triflate, an annulation reagent for the synthesis of heterocycles via epoxidation, aziridination, cyclopropanation, and proton-transfer reactions.

Synthesis Analysis

The synthesis of (2-bromoethyl)diphenylsulfonium triflate involves a two-step process starting from commercially available 2-bromoethanol. The first step is the treatment of 2-bromoethanol with triflic anhydride in pyridine/CH2Cl2 to generate the corresponding 2-bromoethyl triflate. Without purification, this intermediate is then reacted with diphenyl sulfide in refluxing toluene to produce the sulfonium triflate, which is isolated by precipitation from diethyl ether.

Molecular Structure Analysis

Experimental and theoretical charge density analysis of a bromoethyl sulfonium salt has provided insights into the stereochemistry and electron density topology of the sulfonium group. The electropositivity of the S-attached and Br-attached methylene groups has been compared, and it has been noted that the hydrogen atoms on the carbon atom bound to sulfur are more acidic due to their proximity to the positively charged sulfur atom.

Chemical Reactions Analysis

The compound has been shown to be a powerful vinylation reagent in the Sonogashira cross-coupling reactions with terminal alkynes. The vinylation proceeds smoothly under Pd/Cu catalysis at 25 °C, affording a variety of 1- and 2-unsubstituted 1,3-enynes in moderate to excellent yields. This represents the first application of (2-haloethyl)diphenylsulfonium triflate as a CH₂CH₂ transfer source in organic synthesis.

Physical and Chemical Properties Analysis

(2-Bromoethyl)diphenylsulfonium triflate is typically insoluble in petrol-derived solvents and non-polar ethereal solvents but is partially soluble in THF:H2O (2:1) and fully soluble in several organic solvents such as acetone, CHCl3, CH2Cl2, CH3CN, DMSO, DMF, EtOH, MeOH, and THF. It is supplied as a grey to tan amorphous solid and can be stored at room temperature for over two years without significant decomposition or loss of reactivity. The compound's toxicity has not been studied extensively, but due to its potential as a potent alkylating agent, it should be handled with care.

Scientific Research Applications

Application 1: Synthesis of Imidazolinium Salts 

• Summary of the Application : “(2-Bromoethyl)diphenylsulfonium trifluoromethanesulfonate” is used as a vinyl sulfonium salt precursor in the synthesis of imidazolinium salts.
• Methods of Application : A typical procedure involves adding “(2-Bromoethyl)diphenylsulfonium trifluoromethanesulfonate” to a stirred solution of N,N’-bis(2,6-diisopropylphenyl)formamidine and diisopropylethylamine in anhydrous MeCN under a nitrogen atmosphere.
• Results or Outcomes : The reaction leads to the formation of imidazolinium salts.

Application 2: Sulfinylation Reactions 

• Summary of the Application : “(2-Bromoethyl)diphenylsulfonium trifluoromethanesulfonate” is used as a reactant in sulfinylation reactions.
• Methods of Application : The specific methods of application in sulfinylation reactions can vary depending on the specific reaction conditions and the substrates used.
• Results or Outcomes : The outcome of these reactions is the formation of sulfinylated organic compounds.

Safety And Hazards

This compound is classified as an eye irritant (Eye Irrit. 2), skin irritant (Skin Irrit. 2), and may cause respiratory irritation (STOT SE 3). It is recommended to avoid contact with skin and eyes, and to use personal protective equipment such as dust masks, eyeshields, and gloves when handling this compound.

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