Zhuofei Deng, B. Huang, Huajing Xu
Oct 1, 2017
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Influential Citations
4
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Journal
Asian Journal of Organic Chemistry
Abstract
Highly enantioselective Mannich addition reactions of N,S-heterocyclic dibenzo[b,f][1,4]thiazepines as seven-membered cyclic imine substrates with ketones were developed by using proline as an organocatalyst. Substituted dibenzo[b,f][1,4]thiazepines and various unsymmetrical alkyl methyl ketones were used as substrates and optimized reaction conditions offered an efficient method to synthesize optically active 11-substituted 10,11-dihydrodibenzo[b,f][1,4]thiazepine derivatives that contained a carbonyl functional group in 91–99 % ee. Furthermore, we found that the reactions could also be performed on a gram scale, whilst maintaining high yields and enantioselectivities. The carbonyl group of the Mannich products also underwent diastereoselective reduction, thus yielding a new hydroxy-substituted chiral stereogenic center with moderate-to-excellent diastereoselectivities, good yields, and without the loss of enantiomeric excess.