Department of Chemistry, Energy Institute, Institute for Advanced Study, and the Hong Kong Branch of Chinese National Engineering Research Centre for Tissue Restoration & Reconstruction, The Hong Kong University of Science and Technology (HKUST), Clear Water Bay, Kowloon, Hong Kong SAR, China.
HKUST Shenzhen Research Institute, No. 9 Yuexing 1st Rd, 518057, Shenzhen, China.
Nat Commun. 2023 Jan 23;14(1):357. doi: 10.1038/s41467-023-36000-6.
Electricity-driven asymmetric catalysis is an emerging powerful tool in organic synthesis. However, asymmetric induction so far has mainly relied on forming strong bonds with a chiral catalyst. Asymmetry induced by weak interactions with a chiral catalyst in an electrochemical medium remains challenging due to compatibility issues related to solvent polarity, electrolyte interference, etc. Enabled by a properly designed phase-transfer strategy, here we have achieved two efficient electricity-driven catalytic asymmetric bromocyclization processes induced by weak ion-pairing interaction. The combined use of a phase-transfer catalyst and a chiral phosphate catalyst, together with NaBr as the bromine source, constitutes the key advantages over the conventional chemical oxidation approach. Synergy over multiple events, including anodic oxidation, ion exchange, phase transfer, asymmetric bromination, and inhibition of Br decomposition by NaHCO, proved critical to the success.
电催化不对称合成是有机合成中一种新兴的有力工具。然而，不对称诱导迄今为止主要依赖于与手性催化剂形成强键。由于与溶剂极性、电解质干扰等相关的相容性问题，在手性催化剂的电化学介质中通过弱相互作用诱导不对称仍然具有挑战性。通过合理设计的相转移策略，我们在这里实现了两种有效的电驱动催化不对称溴环化过程，其由弱离子对相互作用诱导。与传统的化学氧化方法相比，相转移催化剂和手性磷酸催化剂的联合使用以及 NaBr 作为溴源是关键优势。多个事件的协同作用，包括阳极氧化、离子交换、相转移、不对称溴化以及 NaHCO 抑制 Br 分解，对成功至关重要。
