MHAT-driven copper-catalyzed hydrosilylation of alkenes: a new radical pathway for a less explored regioselectivity

Here, we report the Markovnikov hydrosilylation of alkenes catalyzed by a relatively simple copper(I) species that provides a new radical pathway for catalytic hydrosilylation. Overall, our results are consistent with two subsequent hydrogen atom transfer processes: one that activates the silane and forms the copper hydride (HAT), and another that activates the alkene (MHAT). • New type of mechanism for the transition metal-catalyzed hydrosilylation of alkenes. • Mechanistic pathway relying on two subsequent hydrogen atom transfers: HAT and MHAT. • Copper-based MHAT process performed in the absence of oxidants. • Mild reaction conditions and exclusive Markovnikov regioselectivity • Use of stoichiometric amounts of simple silanes. The synthesis of non-linear organosilicon compounds has received significant attention in recent years owing to their promising potential as fine chemicals. Among the various synthetic approaches, catalytic hydrosilylation of alkenes remains the most direct and atom-economical strategy, with increasing efforts focused on the use of catalysts based on first-row transition metals. Herein, we report an efficient and operationally simple protocol for the copper-catalyzed Markovnikov hydrosilylation of alkenes. Besides the new type of well-defined copper(I)-based catalytic precursors and the excellent yields obtained when using activated alkenes, the experimental evidence is consistent with a mechanism relying on a hydrogen atom transfer from a metal hydride (MHAT), which, to the best of our knowledge, has never been reported for this type of transformation. Moreover, there are only a few examples of this reactivity with copper. Therefore, this work provides a valuable contribution to current knowledge of copper chemistry and MHAT processes, highlighting their potential for the synthesis of organosilicon compounds.