Halogenation Reactions of Alkyl Alcohols Employing Methyl Grignard Reagents.

Grignard reagents are commonly used as carbanion equivalents. Herein, we report an example of Grignard reagents acting as halide nucleophiles to form alkyl iodides and bromides. We establish that Grignard reagents can convert alkyl mesylates into alkyl halides, as well as be employed in a one-pot halogenation reaction starting from alcohols, which proceed through mesylate intermediates. The halogenation reaction is confirmed to occur by an S2 pathway with inversion of configuration and is demonstrated to be efficient on multi-gram scale.