Michael Addition of Phthalimide and Saccharin to Enantiomerically Pure Diesters of BINOL and TADDOLs Derivatives Under Microwave Conditions

Some N-alkyl phthalimides and saccharin derivatives are important in medicinal chemistry. These compounds can act as antipsychotic, anti-inflammatory and lipid lowering agents, among others. Furthermore, saccharin derivatives can complex with various metal ions, such as Mg²⁺, Ca²⁺, Sr²⁺, Pd²⁺, Cu²⁺. One of the most important reactions in synthetic organic chemistry is the conjugate addition of nucleophilic species to the β-carbon of α,β-unsaturated systems. This process allows the construction of carbon backbones it is very valuable from a synthetic point of view. Several attempts in the generation of β-amino derivatives have been reported and the aza-Michael addition reaction is widely recognized as one of the most important carbon-nitrogen bond–forming reaction in organic synthesis. Most of these products have special properties. For instance, the β-amino acids that can be obtained from aza-Michael additions between amines and α,β-unsaturated esters are attractive precursors in preparation of a variety of bioactive molecules and backbone of a variety of drugs. Moreover, the synthesis of β-amino esters has gained considerable attention due to the possibility of generate intermediates for the synthesis of natural products, aminoalcohols, diamines, β-lactams, β-amino acid derivatives and other molecules containing nitrogen. Thus, this reaction provides a simple and appealing route toward synthesis of N-alkyl derivatives of these compounds. In this work, we propose to study the aza-Michael reaction under microwave condition between saccharine and phtalimide with enantiomerically pure diesters of BINOL and TADDOLs derivatives. This methodology allowed us to obtain di-addition products of great synthetic interest with good yields and relatively short reaction times.