Carbene-catalyzed enantioselective sulfonylation of enone aryl aldehydes: a new mode of breslow intermediate oxidation

• Main Authors: Deng, Rui, Wu, Shuquan, Mou, Chengli, Liu, Jianjian, Zheng, Pengcheng, Zhang, Xinglong, Chi, Robin Yonggui
• Other Authors: School of Physical and Mathematical Sciences
• Format: Article
• Language: English
• Published: 2022
• Subjects: Science::Chemistry; Aldehydes; Catalyst Deactivation
• Online Access: https://hdl.handle.net/10356/161331
• Institution: Nanyang Technological University

A carbene-catalyzed sulfonylation reaction between enone aryl aldehydes and sulfonyl chlorides is disclosed. The reaction effectively installs sulfone moieties in a highly enantioselective manner to afford sulfone-containing bicyclic lactones. The sulfonyl chloride behaves both as an oxidant and a nucleophilic substrate (via its reduced form) in this N-heterocyclic carbene (NHC)-catalyzed process. The NHC catalyst provides both activation and stereoselectivity control on a very remote site of enone aryl aldehyde substrates. Water plays an important role in modulating catalyst deactivation and reactivation routes that involve reactions between NHC and sulfonyl chloride. Experimental studies and DFT calculations suggest that an unprecedented intermediate and a new oxidation mode of the NHC-derived Breslow intermediate are involved in the new asymmetric sulfonylation reaction.