Synthesis of Sulfonyl Fluorides from Tertiary Sulfonamides via N-Methylation Using Me-λ3-Iodane

Abstract N,N-Dimethyl tertiary sulfonamides were efficiently activated by Me-λ3-iodane through N-methylation, and the generated electrophilic sulfonyl ammonium salts were converted into sulfonyl fluorides in one pot. The use of Et3N·3HF as the nucleophilic fluoride source is key to obtaining good-to-high yields for various substrates. The optimized protocol enables the utilization of readily available and highly stable sulfonamides as a protecting group for the corresponding sulfonyl fluorides. We have demonstrated the multistep synthesis of sulfonyl fluorides, during which the sulfonyl moiety was protected from strong nucleophiles as a sulfonamide.