- Dual organocatalysis: asymmetric allylic-allylic alkylation of alpha,alpha-dicyanoalkenes and Morita-Baylis-Hillman carbonates.
Dual organocatalysis: asymmetric allylic-allylic alkylation of alpha,alpha-dicyanoalkenes and Morita-Baylis-Hillman carbonates.
Chemistry (Weinheim an der Bergstrasse, Germany) (2009-01-10)
Hai-Lei Cui, Jing Peng, Xin Feng, Wei Du, Kun Jiang, Ying-Chun Chen
PMID19132709
ABSTRACT
The first highly enantioselective allylic-allylic alkylation of alpha,alpha-dicyanoalkenes and Morita-Baylis-Hillman carbonates by dual catalysis of (DHQD)(2)AQN and (S)-BINOL has been investigated. Excellent stereoselectivities have been achieved for a broad spectrum of substrates (d.r. > 99:1, up to 99 % ee). The multifunctional allylic products could be efficiently converted to a range of complex chiral cyclic frameworks. EWG = electron-withdrawing group, (DHQD)(2)AQN = hydroquinidine (anthraquinone-1,4-diyl) diether, (S)-BINOL = (S)-(-)-1,1'-bi-2-naphthol.
MATERIALS