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Updated: Dec 1, 2025

Metal-free Synthesis of Ynones from Acyl Chlorides and Potassium Alkynyltrifluoroborate Salts
Published on: February 24, 2015
C2-Selective C-H Methylation of Heterocyclic N-Oxides with Sulfonium Ylides
Won An1, Su Bin Choi1, Namhoon Kim2,3
1School of Pharmacy, Sungkyunkwan University, Suwon 16419, Republic of Korea.
Abstract:
A redox-neutral C2-selective methylation of heterocyclic N-oxides with sulfonium ylides is described herein. This report presents unprecedented findings for the utility of sulfonium ylides as the methylation source of N-heterocycles beyond the Corey-Chaykovsky reaction. Intriguingly, pyrrolidine plays a significant role in minimizing the reductive C2-methylation process. This method is characterized by its mild conditions, simplicity, and excellent site selectivity. The applicability of the developed protocol is showcased by the late-stage methylation and sequential transformations of complex drug molecules.
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