Catalytic Asymmetric Acyloin Rearrangements of α‑Ketols, α‑Hydroxy Aldehydes, and α‑Iminols by N,N′‑Dioxide–Metal Complexes
journal contributionposted on 17.06.2020, 16:14 by Li Dai, Xiangqiang Li, Zi Zeng, Shunxi Dong, Yuqiao Zhou, Xiaohua Liu, Xiaoming Feng
A highly enantioselective acyloin rearrangement of cyclic α-ketols has been developed with a chiral Al(III)–N,N′-dioxide complex as catalyst. This strategy provided an array of optically active 2-acyl-2-hydroxy cyclohexanones in moderate to good yields with high enantioselectivities. The asymmetric isomerizations of acyclic α-hydroxy aldehydes and α-iminols were achieved as well under modified conditions, affording the corresponding chiral α-hydroxy ketones and α-amino ketones in moderate results. Moreover, further transformations of product to enantioenriched diols were carried out.