β‐Borylation of α,β‐Unsaturated Carbonyl Compounds: Advances in Catalysis and Synthetic Applications

ABSTRACT

β‐Borylation of α,β‐unsaturated carbonyl compounds is a valuable strategy for preparing β‐borylated carbonyl derivatives that combine carbonyl reactivity with the synthetic versatility of carbon–boron bonds. This review summarizes recent advances in transition‐metal‐catalyzed and metal‐free β‐borylation, with emphasis on catalyst design, mechanisms, substrate scope, and synthetic utility. Platinum and rhodium systems provided early mechanistic foundations, while copper catalysis has become the most practical and broadly developed platform. Nickel, gold, and iridium catalysts offer complementary reactivity, including ester‐ and amide‐selective borylation, heterogeneous B–B/Si–B activation, and vinylic C–H borylation. Metal‐free approaches based on N‐heterocyclic carbenes, Brønsted base/alcohol systems, and phosphines further expand the activation modes of diboron reagents. Selected examples of Suzuki–Miyaura cross‐coupling, oxidation, fluorination, organotrifluoroborate stabilization, and one‐pot transformations highlight the synthetic potential of β‐borylated carbonyl intermediates. Current limitations and future opportunities in product stability, substrate generality, stereochemical transfer, and post‐borylation functionalization are also discussed.