Silver-Promoted Synthesis of 5-[(Pentafluorosulfanyl)methyl]-2-oxazolines

Abstract

The synthesis of 5-[(pentafluorosulfanyl)­methyl]-2-oxazolines is reported. The use of a silver promoter allows the intramolecular cyclization of N-[2-chloro-3-(pentafluorosulfanyl)­propyl]­amide to occur without elimination of the chlorine atom, a reaction pathway typically observed for β-chloro-SF5-alkyl compounds. The products, potentially valuable SF5-containing heterocycles, are obtained in up to 97% yield.

Synthesis of 5‐[(Pentafluorosulfanyl)methyl]‐γ‐butyrolactones via a Silver‐Promoted Intramolecular Cyclization Reaction

“…Having a series of 4‐chloro‐5‐(pentafluorosulfanyl)pentanoic acids in hands, we selected 2a as the model substrate for the optimization of the intramolecular cyclization (Scheme ). We then employed the conditions developed in our prior work on the synthesis of 5‐[(pentafluorosulfanyl)methyl]‐2‐oxazolines to set a starting point. When using AgOTf (1.1 equiv.)…”

“…While a number of methods have been reported for the synthesis of 5‐trifluoromethyl‐γ‐butyrolactones, the preparation of the corresponding 5‐(pentafluorosulfanyl)methyl‐substituted lactones remains unknown. We have recently reported the synthesis of 5‐[(pentafluorosulfanyl)methyl]‐2‐oxazolines using a silver‐promoted cyclization reaction of N ‐(2‐chloro‐3‐(pentafluorosulfanyl)propyl)amides (Scheme b) . Inspired by this work, we report herein its extension for the preparation of 5‐[(pentafluorosulfanyl)methyl]‐γ‐butyrolactones (Scheme c).…”

Recent Advances in the Synthesis and Medicinal Chemistry of SF5 and SF4Cl Compounds

“…In this context, Paquin and co-workers successfully applied a silver-promoted intramolecular cyclization to a series of N-[2-chloro-3-(SF 5 )-propyl]amides to afford a library of 5-[(SF 5 )-methyl]-2-oxazolines (Scheme 25). 27 It is worth noting that the reaction occurred without elimination of the chlorine atom, a typical side reaction observed for -chloro-SF 5 -alkyl compounds. The target SF 5 -containing heterocycles were obtained in 40-97% yields.…”

Pentafluorosulfanyl Chloride

“…The subsequent cyclization in the presence of silver triflate proceeded through chlorine substitution rather than leading to elimination products typically obtained with the aid of various bases. 39 Additions to Enol Ethers.…”