Michaeladdition reaction of α-branched aldehydes to β-nitroacrylates was successfully carried out by using a mixed catalyst consisting of a primary amino acid, L-phenylalanine, and its lithium salt to give β-formyl-β′-nitroesters having a quaternary carbon centre in good yields (up to 85%) with high enantioselectivity (up to 98% ee). By using benzyl β-nitroacrylates as Michael acceptors, the obtained
straightforward and general synthesis of nitroolefins fromnitricoxide (NO) and olefins is presented. The direct nitration of aromatic olefins, allyl compounds, and acrylic acid derivatives proceeds smoothly at room temperature with high regioselectivity and good yields. The advantages of this novel procedure compared to established nitration procedures are demonstrated.
A simple nitration of electrophilic alkenes with tetranitromethane in the presence of triethylamine. Synthesis of functionalized β-nitroalkenes
作者:Yulia A. Volkova、Elena B. Averina、Yuri K. Grishin、Victor B. Rybakov、Tamara S. Kuznetsova、Nikolai S. Zefirov
DOI:10.1016/j.tetlet.2011.04.012
日期:2011.6
convenient method for the preparation of functionalized β-nitroalkenes based on the nitration of α,α-di- and α,α,β-trisubstituted unsaturated aldehydes, ketones and esters with tetranitromethane in the presence of triethylamine is described. Series of substituted β-nitroalcohols and β-nitroalkenes are obtained in good yields under mild conditions.