HBF₄‐Catalysed Nucleophilic Substitutions of Propargylic Alcohols

Abstract

The activity of HBF4 (aqueous solution) as a catalyst in propargylation reactions is presented. Diverse types of nucleophiles were employed in order to form new C–O, C–N and C–C bonds in technical acetone and in air. Good to excellent yields and good chemoselectivities were obtained using low acid loading (typically 1 mol-%) under simple reaction conditions.

Taming Brønsted Acid Reactivity: Nucleophilic Substitutions of Propargylic Alcohols with N-Nucleophiles Mediated by Phosphorus-Based Brønsted Acid Catalysts

“…(HO)P(OEt) 2 A and (HO)P(O)(OPh) 2 B were purchased from Sigma-Aldrich with 98 and 99% purities, respectively. Propargylic alcohols 1a , 6 1b , 6 1c , 6 1d , 6 1e , 19 and 1f (16) were prepared according to the literature procedures. Column chromatography and thin-layer chromatography were performed on silica gel (Kieselgel 60), using UV light and a phosphomolybdic acid dip to visualize the products.…”

“…Sulfonic acids 4 and phosphomolybdic acid on silica 5 have been used with a wide range of C-, N-, and O-nucleophiles in S N 1 reactions of propargylic alcohols, and we similarly reported the use of aqueous HBF 4 . 6 These catalysts are compatible with air and reagent-grade solvents, but they are obviously limited by the basicity of the chosen nucleophile. Every system has to be optimized to avoid competitive Meyer–Schuster and Rupe rearrangements.…”

Designs and Strategies for the Halo‐Functionalization of Diazo Compounds

“…HBF 4 is a benign fluoride source known as a versatile acid owing to its diverse applications in both industrial and academic synthesis . HBF 4 can be used as a catalyst for various reactions, including the acylation of aldehydes, Friedel–Crafts alkylation of 1‐aryl‐1‐alkanols, amidation of olefins, and the Bignelli reaction, and as a reagent in vinylidene metal complex synthesis and nucleophilic fluorination.…”

Insight into the Selectivity and Mechanism of Surfactin Containing Multiple Dissociated Carboxyls with 1-Bromoacetylpyrene in Fluorescent Derivatization

“…In this reaction, surfactin was activated by TEA and exposed more nucleophilic groups to attack the BAP, which has an α-C and is prone to come up with nucleophilic substitution. [28][29][30] Because of the steric-hindrance effect, only the carboxyl in Asp residue was labeled with BAP. After derivatization, the D-surfactin was still connected with TEA in the carboxyl in Glu residue.…”