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.