Ruthenium-Catalyzed One-Pot Synthesis of (E)-(2-Arylvinyl)boronates through an Isomerization/Cross-Metathesis Sequence from Allyl-Substituted Aromatics

We described the efficient preparation of (E)‐(2‐arylvinyl)boronates from allylbenzene derivatives on the basis of an isomerization/cross‐metathesis sequence catalyzed by a modified Hoveyda–Grubbs catalyst. The implementation of the experimental procedure was simple and compatible with a large variety of substrates. This methodology provides a new chemical transformation not described to date. Allyl‐substituted aromatics can thus be converted into diversely functionalized compounds, such as (E)‐stilbene derivatives or (E)‐vinyl azides, in only two steps. A new stereoselective route to (E)‐alkenylboronates starting from the isomerization of allyl‐substituted aromatics is developed. This simple process catalyzed by a modified Hoveyda–Grubbs catalyst is based on an isomerization/cross‐metathesis sequence that is compatible with a large variety of allylbenzene derivatives.