A Mild Disilane-Enabled Halide-to-Deuterium Manifold With D₂O for Aryl and Benzylic Halides

Selective deuterium incorporation into aromatic molecules is important in mechanistic studies, medicinal chemistry, and isotope-enabled molecular design, yet methods that combine inexpensive deuterium sources, mild reducing conditions, broad functional-group tolerance, and high deuterium incorporation remain scarce. Here we report a disilane-enabled palladium-catalyzed dehalogenative deuteration of aryl and benzylic halides using D₂O as the deuterium source. The reaction proceeds under mild conditions across a broad substrate range, furnishing more than 60 deuterated products in generally high yields and with typically >95% deuterium incorporation. Carboxylic acids, reduction-sensitive functional groups, and π-unsaturated motifs are all tolerated, and the protocol is readily scalable. Mechanistic studies are consistent with a disilane-assisted pathway in which fluoride-mediated activation of the disilane promotes the conversion of arylpalladium intermediates to deuterated products using D₂O as the deuterium source. This operationally simple method provides direct access to selectively deuterated arenes from readily available halides and establishes disilanes as pathway-enabling reagents for palladium-catalyzed dehalogenative functionalization.