A small set of easily available epi-cinchona based thiourea organocatalysts have been synthesized and tested in enantioselective Michael addition of nitroalkanes to chalcones. These bifunctional catalyst systems promoted the conjugate additions with high enantioselectivities and chemical yields. The extension of this methodology was further explored to encompass alpha,beta-unsaturated N-acylpyrroles, as a chalcone mimic. Functionally, the N-acylpyrrole moiety in the adduct acts as an ester surrogate; therefore, it can easily be transformed to various valuable and biologically relevant compounds. This approach allowed the concise stereoselective synthesis of (R)-rolipram.
A small set of easily available epi-cinchona based thiourea organocatalysts have been synthesized and tested in enantioselective Michael addition of nitroalkanes to chalcones. These bifunctional catalyst systems promoted the conjugate additions with high enantioselectivities and chemical yields. The extension of this methodology was further explored to encompass alpha,beta-unsaturated N-acylpyrroles, as a chalcone mimic. Functionally, the N-acylpyrrole moiety in the adduct acts as an ester surrogate; therefore, it can easily be transformed to various valuable and biologically relevant compounds. This approach allowed the concise stereoselective synthesis of (R)-rolipram.
An Approach for Rapid Increase in Molecular Complexity: Atom Economic Routes to Fused Polycyclic Ring Systems
作者:Barry M. Trost、Veronika Ehmke
DOI:10.1021/ol5009872
日期:2014.5.16
developed. This process generates alkynyl-substituted cyclopentanes in high yields and diastereo- and enantioselectivities. These chiral precursors are employed for the atom economic assembly of fused polycyclic hydrocarbons with hydroindene, hydroazulene, and hydrocyclopentanaphthalene scaffolds by consecutive cycloaddition reactions.
<i>Epi</i>-Cinchona Based Thiourea Organocatalyst Family as an Efficient Asymmetric Michael Addition Promoter: Enantioselective Conjugate Addition of Nitroalkanes to Chalcones and α,β-Unsaturated <i>N</i>-Acylpyrroles
作者:Benedek Vakulya、Szilárd Varga、Tibor Soós
DOI:10.1021/jo702692a
日期:2008.5.1
A small set of easily available epi-cinchona based thiourea organocatalysts have been synthesized and tested in enantioselective Michael addition of nitroalkanes to chalcones. These bifunctional catalyst systems promoted the conjugate additions with high enantioselectivities and chemical yields. The extension of this methodology was further explored to encompass alpha,beta-unsaturated N-acylpyrroles, as a chalcone mimic. Functionally, the N-acylpyrrole moiety in the adduct acts as an ester surrogate; therefore, it can easily be transformed to various valuable and biologically relevant compounds. This approach allowed the concise stereoselective synthesis of (R)-rolipram.