Amberlyst A-27, an Efficient Heterogeneous Catalyst for the Michael Reaction of Nitroalkanes with β-Substituted Alkene Acceptors

摘要

The Michael addition of nitroalkanes to electrophilic double bonds provides a convenient method for the preparation of a number of useful synthetic intermediates since the nitro group can be transformed into various functionalities. Different organic bases such as tetramethylguanidine, potassium fluoride/18-crown-6, sodium hydride/18-crown-6, diisopropylamine, potassium tert-butox-ide, tri-n-butylphosphine, triphenyphosphine,1,8-diazobicyclo[5.4.0]undec-7-ene, and tetrabutylammonium fluoride have been used in homogeneous solutions. Under these conditions, multiple Michael adducts are often formed in significant amounts. This problem is most acute in the case of vinylcarbonyl derivatives.