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Organocatalyzed Asymmetric 1,6-Conjugate Addition of para-Quinone Methides with Dicyanoolefins

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journal contribution
posted on 04.02.2016, 16:06 authored by Xuanyi Li, Xiuyan Xu, Weiwei Wei, Aijun Lin, Hequan Yao
A chiral thiourea catalyzed asymmetric 1,6-conjugate addition of para-quinone methides with dicyanoolefins has been developed. The reaction provided an efficient approach to the synthesis of chiral diarylmethine skeletons in good yields (up to 99% yield) with high diastereo- and enantioselectivity (>20:1 dr and up to 99.5:0.5 er), also on a gram scale. The preliminary mechanistic study showed that the remote stereocontrol was achieved through intermolecular hydrogen-bond interaction between the chiral thiourea catalyst and the para-quinone methides directly for the first time.