摘要:
Asymmetric conjugate addition of ethyl 4-chloro-3-oxobutanoate to nitroalkenes and subsequent intramolecular cyclization had been developed. This one-pot reaction provided tetronic acid derivatives in good yields and with excellent enantioselectivities. 6'-Demethyl quinine was found to be the best catalyst for the conjugate addition and AcOLi was identified as the best base for the intramolecular cyclization. Various beta-aryl, heteroaryl, and alkyl nitroalkenes are generally applicable in the reaction. (C) 2012 Elsevier Ltd. All rights reserved.