Asymmetric organocatalytic synthesis of highly substituted cyclohexenols by domino double-michael reactions of 1-hydroxy-1,4-dien-3-ones and 2-alkylidenemalononitriles

A facile asymmetric synthetic protocol to afford 2,6-disubstituted 4-hydroxy-3-oxocyclohex-3-ene-1,1-dicarbonitriles has been developed through the domino double-Michael addition of 1,5-disubstituted 1-hydroxy-1,4-dien-3-ones to 2-alkylidenemalononitriles using quinine as the catalyst. This simple organocatalytic domino process provides access to various highly functionalized chiral 4-hydroxy-3-oxocyclohex-3-enes, which are the rarely reported chiral diketo cyclohexane analogues, in moderate-to-good yields and enantioselectivities and with excellent diastereoselectivities (>25:1 dr). An effective asymmetric organocatalytic synthesis of polysubstituted cyclohexenes from 1-hydroxy-1,4-dien-3-ones and 2-alkylidenemalononitriles by a domino double-Michael reaction sequence using quinine as catalyst has been achieved. The products were obtained in moderate-to-good yields (up to 96) and enantioselectivities (up to 92 ee).