Doubly stereocontrolled asymmetric Michael addition of acetylacetone to nitroolefins promoted by an isosteviol-derived bifunctional thiourea
作者:Zhi-wei Ma、Yu-xia Liu、Li-juan Huo、Xiang Gao、Jing-chao Tao
DOI:10.1016/j.tetasy.2012.03.020
日期:2012.4
A novel class of chiral bifunctionalthioureas bearing a chiral lipophilic beyerane scaffold and a tertiary amino group was designed and prepared. The thioureas were proven to be effective for catalyzing the doubly stereocontrolled asymmetricMichaeladdition between acetylacetone and nitroolefins. The corresponding adducts were obtained in high yields (up to 95%) and with good to excellent enantioselectivities
A highly regio- and enantioselective organocatalyzed Michael addition of malonates to nitrodienes
作者:Raghunath Chowdhury、Ganga B. Vamisetti、Sunil K. Ghosh
DOI:10.1016/j.tetasy.2014.02.007
日期:2014.4
An organocatalyzed direct Michael addition of unsubstituted/substituted malonates, acetoacetate, or acetylacetones to conjugatednitrodienes using a cinchona alkaloid-based thiourea catalyst is disclosed. The addition products were formed in high yields and regioselectivity. The enantioselectivities of the addition products were high in most cases and could significantly be improved upon by a single