Asymmetric Synthesis of γ-Nitroesters by an Organocatalytic One-Pot Strategy
作者:Kim L. Jensen、Pernille H. Poulsen、Bjarke S. Donslund、Fabio Morana、Karl Anker Jørgensen
DOI:10.1021/ol3002514
日期:2012.3.16
An enantioselective synthesis of γ-nitroesters by a one-pot asymmetric Michaeladdition/oxidative esterification of α,β-unsaturatedaldehydes is presented. The procedure is based on merging the enantioselective organocatalytic nitroalkane addition with an N-bromosuccinimide-based oxidation. The γ-nitroesters are obtained in good yields and enantioselectivities, and the method provides an attractive
An efficient enantioselective method for asymmetric Michael addition of nitroalkanes to α,β-unsaturated aldehydes
作者:Yongcan Wang、Pengfei Li、Xinmiao Liang、Tony Y. Zhang、Jinxing Ye
DOI:10.1039/b717000a
日期:——
The addition of nitroalkanes to alpha,beta-unsaturated aldehydes under the catalysis of (S)-2-(diphenyl(trimethylsilyloxy)methyl)pyrrolidine and lithium acetate as additive afforded gamma-nitroaldehydes in good yield and up to 97% ee.
Reactivity and Selectivity of Iminium Organocatalysis Improved by a Protein Host
作者:Alexander R. Nödling、Katarzyna Świderek、Raquel Castillo、Jonathan W. Hall、Antonio Angelastro、Louis C. Morrill、Yi Jin、Yu-Hsuan Tsai、Vicent Moliner、Louis Y. P. Luk
DOI:10.1002/anie.201806850
日期:2018.9.17
There has been growing interest in performing organocatalysis within a supramolecular system as a means of controlling reaction reactivity and stereoselectivity. Here, a protein is used as a host for iminium catalysis. A pyrrolidine moiety is covalently linked to biotin and introduced to the proteinhost streptavidin for organocatalytic activity. Whereas in traditional systems stereoselectivity is
Cyclic amines such as 1,2,3,4-tetrahydroisoquinoline undergo regiodivergent annulation reactions with 4-nitrobutyraldehydes. These redox-neutral transformations enable the asymmetric synthesis of highly substituted polycydic ring systems in just two steps from commercial materials. The utility of this process is illustrated in a rapid synthesis of (-)-protoemetinol. Computational studies provide mechanistic insights and implicate the elimination of acetic acid from an ammonium nitronate intermediate as the rate-determining step.