华中师范大学化学学院陈加荣研究团队研制了光氧化还原-镍-氢原子转移三重催化 ；β；-酮羰基化合物与简单烯烃的直接不对称α。这一研究成果于2025年2月12日发表在国际顶尖学术期刊《德国应用化学》上。

该课题组提出了一种结合光氧化还原、手性刘易斯酸和氢原子转移（HAT）催化剂的协同三重催化系统，以简单烯烃为烷基化剂，实现了β-酮羰基化合物的直接不对称α-烷基化。通过在可见光下将多功能手性镍刘易斯酸与铱光氧化还原催化剂和硫酚催化剂结合，研究人员开发了一种高效的过程，该过程是暂时同步的，以促进电子和氢转移的新机制。这种三重催化方法使β-酮羰基化合物与低活性烯烃和非活性烯烃的分子间偶联成为可能。这种氧化还原-中性方案提供了一种原子和阶梯经济的途径，可以从原料化学物质中对映选择性地合成具有全碳四元立体中心的高价值分子，同时只消耗光子。

据悉，虽然羰基化合物与活化烯烃的不对称α-烷基化已经建立，但由于这些离子过程中的极性不匹配，将这种方法扩展到低活化或非活化烯烃仍然是一个重大挑战。另一种方法是将母体羰基化合物活化成亲电的α-羰基自由基，这有可能克服这一限制。然而，缺乏有效的催化体系阻碍了这种策略的广泛采用，特别是在催化不对称反应领域。

附：英文原文

Title: Direct Asymmetric α-Alkylationof  β-Ketocarbonyl Compounds with Simple Olefins by Photoredox-Nickel-Hydrogen Atom Transfer Triple Catalysis

Author: Xue-Song Zhou, Zi-Qing Li, Wen-Yuan Qu, Zhi-Han Zhang, Wen-Jing Xiao, Jia-Rong Chen

Issue&Volume: 2025-02-12

Abstract: Although the asymmetric α-alkylation of carbonyl compounds with activated olefins has already been established, extending this methodology to less activated or nonactivated olefins remains a significant challenge due to the polarity mismatch in these ionic processes. An alternative approach involves the activation of the parent carbonyl compounds into electrophilic α-carbonyl radicals, which could potentially overcome this limitation. However, the lack of efficient catalytic systems has impeded the wide adoption of this strategy, particularly in realm of the catalytic asymmetric reactions. Here, we present a cooperative triple catalytic system that integrates photoredox, chiral Lewis acid, and hydrogen atom transfer (HAT) catalysts to achieve a direct asymmetric α-alkylation of β-ketocarbonyl compounds using simple olefins as alkylating agents. By combining a multifunctional chiral nickel Lewis acid with an iridium photoredox catalyst and a thiophenol catalyst under visible light, we have developed a highly efficient process that is temporally synchronized to facilitate a novel mechanism of electron and hydrogen transfer. This triple catalytic approach enables the intermolecular coupling of β-ketocarbonyl compounds with both less and non-activated olefins. This redox-neutral protocol provides an atom- and step-economic route to enantioselectively synthesize high-value molecules featuring an all-carbon quaternary stereocenter from feedstock chemicals, while only consuming photons.

DOI: 10.1002/anie.202424915

Source: https://onlinelibrary.wiley.com/doi/10.1002/anie.202424915