Highly Enantioselective Organocatalytic Conjugate Addition of Nitromethane to α,β-Unsaturated Aldehydes: Three-Step Synthesis of Optically Active Baclofen
作者:Liansuo Zu、Hexin Xie、Hao Li、Jian Wang、Wei Wang
DOI:10.1002/adsc.200700353
日期:2007.12.10
An efficient, organocatalytic, highlyenantioselective, conjugateaddition reaction of nitromethane with α,β-unsaturated aldehydes has been developed. The process serves as the key step for a practical 3-step synthesis of chiral baclofen, an antispastic drug.
Highly Active Water-Soluble and Recyclable Organocatalyst for the Asymmetric 1,4-Conjugate Addition of Nitroalkanes to α,β-Unsaturated Aldehydes
作者:Subrata K. Ghosh、Zilong Zheng、Bukuo Ni
DOI:10.1002/adsc.201000344
日期:2010.10.4
A novel strategy for the catalyticasymmetric conjugate addition of nitroalkanes to α,β-unsaturatedaldehydes in aqueous media has been developed by using diarylprolinol silyl ether in combination with benzoic acid as a water-soluble organocatalyst providing the desired adducts in good to excellent enantioselectivities (up to 95% ee). This catalyst can be recycled at least five times with only a slight
Remote Sulfonamido Group Enhances Reactivity and Selectivity for Asymmetric Michael Addition of Nitroalkanes to α,β-Unsaturated Aldehydes
作者:Yu-Chao Huang、Biing-Jiun Uang
DOI:10.1002/asia.201402516
日期:2014.9
The pyrrolidine–camphorsulfonamide‐based catalyst 1 a catalyzes the enantioselectiveconjugateaddition of nitroalkanes to α,β‐unsaturated aldehydes in the presence of five equivalents of water in iPrOH to give the corresponding chiral Michael adducts in good yields and high enantioselectivities (up to 99 % ee) with a catalystloading as low as 1 mol %.
Diphenylprolinol Silyl Ether as Catalyst of an Asymmetric, Catalytic, and Direct Michael Reaction of Nitroalkanes with α,β-Unsaturated Aldehydes
作者:Hiroaki Gotoh、Hayato Ishikawa、Yujiro Hayashi
DOI:10.1021/ol702545z
日期:2007.12.1
A catalyticenantioselective direct conjugate addition of nitroalkanes to alpha,beta-unsaturated aldehydes using diphenylprolinolsilylether as an organocatalyst has been developed. Using this methodology as a key step, short syntheses of therapeutically useful compounds have also been accomplished.
hydrazine delivered a hexahydroindazole intermediate, which underwent N(2)‐substitution with various electrophiles (alkyl halides, acyl chlorides, phenyl isocyanate). The resulting N(2)‐substituted hexahydroindazoles could be reduced with LiBEt3H in THF to the target compounds. In addition, a N(2)‐thiobenzoyl and some N(2)‐carbamoyl derivatives as well as a N(1)‐substituted octahydroindazole were synthesized