Baumann James E, Chung Crystal P, Lalic Gojko
Department of Chemistry, University of Washington, 109 Bagley Hall, 98195, Seattle, WA, USA.
Angew Chem Int Ed Engl. 2024 Feb 5;63(6):e202316521. doi: 10.1002/anie.202316521. Epub 2023 Dec 28.
Alkenes are an important class of organic molecules found among synthetic intermediates and bioactive compounds. They are commonly synthesized through stoichiometric Wittig-type olefination of carbonyls and imines, using ylides or their equivalents. Despite the importance of Wittig-type olefination reactions, their catalytic variants remain underdeveloped. We explored the use of transition metal catalysis to form ylide equivalents from readily available starting materials. Our investigation led to a new copper-catalyzed olefination of imines with alkenyl boronate esters as coupling partners. We identified a heterobimetallic complex, obtained by hydrocupration of the alkenyl boronate esters, as the key catalytic intermediate that serves as an ylide equivalent. The high E-selectivity observed in the reaction is due to the stereoselective addition of this intermediate to an imine, followed by stereospecific anti-elimination.
烯烃是一类重要的有机分子，存在于合成中间体和生物活性化合物中。它们通常通过羰基和亚胺的化学计量 Wittig 型烯烃化反应来合成，使用叶立德或其等价物。尽管 Wittig 型烯烃化反应很重要，但其催化变体仍未得到充分发展。我们探索了使用过渡金属催化从易得的起始原料形成叶立德等价物。我们的研究导致了一种新的铜催化的以烯基硼酸酯为偶联伙伴的亚胺烯烃化反应。我们确定了一种通过烯基硼酸酯的氢化铜化得到的异双金属配合物，作为充当叶立德等价物的关键催化中间体。反应中观察到的高 E 选择性是由于该中间体对亚胺的立体选择性加成，随后是立体特异性反消除。
