Enantioselective organocatalytic Michael-hemiketalization catalyzed by a trans-bifunctional indane thiourea catalyst
作者:Yaojun Gao、Qiao Ren、Swee-Meng Ang、Jian Wang
DOI:10.1039/c1ob05404j
日期:——
An efficient, convenient and enantioselective Michael-hemiketalization reaction has been developed for the synthesis of naphthoquinones. In this work, a novel trans-bifunctional indane thiourea catalyst has been reported to promote this process to afford high yields (up to 99%) and high to excellent enantiomeric excesses (90–98% ee).
An organocatalyticenantioselectiveMichaeladdition of 2-hydroxy-1,4-naphthoquinone to β,γ-unsaturatedα-oxoesters has been developed. The process was promoted by bifunctional chiral amine derived squaramides according to a hydrogen-bonding mediated activation mechanism and afforded the chiral adducts in high yields (up to 88 %) and excellent enantioselectivity (up to 98 % ee) under mild conditions