연세대학교 이과대학 화학과

일시: 2023년 9월 21일 오후 5시
장소: 과학관 B131호
초록: The efficient generation of structural complexity from simple starting inputs is one of the main goals that we stride toward in synthetic chemistry. In this regard, using transition metal-catalyzed strategies as a key bond-forming step can provide straightforward routes to synthesizing bioactive and functionalized structural motifs. In the first part of my talk, I will discuss the journey toward the asymmetric synthesis of (-)-naltrexone, an opioid antagonist used extensively for managing opioid drug abuse and addiction. Critical bond disconnections of the synthesis will be highlighted, including a Rh-catalyzed C–H alkenylation and electrocyclization, an acidcatalyzed Friedel-Craft cyclization to generate the morphinan core, and a novel latestage Cu-catalyzed hydroxylation strategy. For the second part of my talk, I will present a facile multicomponent strategy using C-H bond substrates, dienes, and a third electrophile to access quaternary centers containing homoallylic alcohols or nitriles. This methodology employs a Cp* cobalt catalyst which enables a chair-like transition state that explains the stereoselectivity or the level of substitution of the diene component. Lastly, I will be discussing a dual Ni/photoredox catalyzed methodology to enable C(sp3)−C(sp3) bond formation to generate β-functionalized amines via cross-coupling between aziridines and aliphatic alcohols activated as benzaldehyde dialkyl acetals. A detailed mechanistic study result will be discussed, elucidating that Ni(II) azametallacycle, conventionally proposed in aziridine crosscoupling, is not an intermediate in the productive cross-coupling. Rather, aziridine activation proceeds via Ni(I) oxidative addition.