A redox-neutral C2-selective methylation of heterocyclic -oxides with sulfonium ylides is described herein. This report presents unprecedented findings for the utility of sulfonium ylides as the methylation source of -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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