Seminar Prof. Yunmi Lee [Kwangwoon Univ.] - Catalytic Regiodivergent Hydrofunctionalization of Allenes using Diisobutylaluminum Hydride
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Date: 2026/5/14 (THU) 5pm
Venue: Science Hall B133
Abstract:
Allenes, featuring orthogonal π-systems within a cumulated diene framework, exhibitunique reactivity and serve as versatile building blocks in organic synthesis. However, theirselective hydrofunctionalization remains challenging due to intrinsic difficulties in controllingregio- and stereoselectivity. To address these limitations, we have developed a catalyticregiodivergent hydrofunctionalization platform for di- and trisubstituted allenes usingdiisobutylaluminum hydride (DIBAL-H) as a key hydride source. First, a Cu-catalyzedhydroalumination of allenes was established, enabling highly regioselective formation of allylaluminum intermediates. These organoaluminum species serve as versatile synthetichandles and undergo diverse C–C and C–heteroatom bond-forming reactions withelectrophiles such as CO2, isocyanides, cyanating agents, aldehydes, and iminium salts. Thisstrategy provides rapid access to structurally diverse molecules, including products bearingquaternary carbon centers, with excellent yields and selectivity. Furthermore, we developed a regiodivergent hydroarylation platform that enables selective α-, β-, and γ-arylation of unactivated allenes through catalyst control. For α- and γ-selective hydroarylation, a cooperative Cu/Pd dual catalytic system employing DIBAL-H was developed, whereligand-controlled transmetallation governs regioselectivity. In contrast, a complementarypalladium-catalyzed β-selective hydroarylation provides efficient access to tetra-substitutedalkenes with high stereoselectivity. This operationally simple, modular, and regioselectiveprotocol offers a general platform for allene hydrofunctionalization and significantly expandsthe synthetic utility of Cu–H, Pd–H catalysis and organoaluminum intermediates in modern allene chemistry.