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DOI: 10.1055/s-0030-1259451
Synthesis of Cyclohexanones via Double-Conjugate Addition of Dienones
X.-m. Li, B. Wang, J.-m. Zhang, M. Yan*
Sun Yat-sen University, Guangzhou, P. R. of China
Publication History
Publication Date:
16 February 2011 (online)
Significance
Yan and co-workers report an asymmetric double-conjugate addition of malononitrile 2 to dienones 1. Using 9-amino-9-deoxyepiquinine 3 as catalyst and TFA as a co-catalyst, a series of 3,4,4,5-tetrasubstituted cyclohexanones 4 were obtained in good yields and excellent enantioselectivities. Both electron-donating and -withdrawing substituents at the aryl group were well tolerated. However, monoalkyl-substituted or dialkyl dienones showed low or no reactivity under these reaction conditions. Takemoto’s bifunctional catalyst 5 could also promote the reaction, though with lower enantioselectivity (60% ee) and lower yield (25%), while its primary amine analogue 6 did not show any catalytic activity under the same reaction conditions.