In 2022,Cromwell, Simon; Sutio, Randy; Zhang, Changhe; Such, Georgina K.; Lupton, David W. published an article in Angewandte Chemie, International Edition. The title of the article was 《Lewis Base Catalyzed Synthesis of Sulfur Heterocycles via the C1-Pyridinium Enolate》.Formula: C4H7BrO2 The author mentioned the following in the article:
Herein, a reaction cascade in which a C1-pyridinium enolate undergos addition to dithioesters, trithiocarbonates and xanthates was reported. The reaction provided access to a range of dihydrothiophenes I [R = cyclohexyl, Ph, SBn, etc.; R1 = R2 = H; R1 = Me; R2 = CN, Ph] and dihydrothiopyrans II [R3 = H, Me, OMe, F] and III [R4 = H, Me, F]. Mechanistic investigations, including isolation of intermediates, electronic correlation, and kinetic isotope effect studies support the viability of an activated acid intermediate giving rise to the C1-pyridinium enolate which undergoes turnover limiting cyclization. Subsequent formation of a β-thiolactone regenerates the catalyst with loss of carbon oxysulfide providing the observed products. The experimental part of the paper was very detailed, including the reaction process of 4-Bromobutanoic acid(cas: 2623-87-2Formula: C4H7BrO2)
4-Bromobutanoic acid(cas: 2623-87-2) belongs to carboxylic acids. The chief chemical characteristic of the carboxylic acids is their acidity. They are generally more acidic than other organic compounds containing hydroxyl groups but are generally weaker than the familiar mineral acids (e.g., hydrochloric acid, HCl, sulfuric acid, H2SO4, etc.).Formula: C4H7BrO2
Referemce:
Bromide – Wikipedia,
bromide – Wiktionary