Asymmetric Michael addition reactions using ethyl (S)-4,4- dimethylpyroglutamate as a chiral auxiliary

Article abstract of DOI:10.1016/S0040-4039(98)02648-3

Ethyl 4,4-dimethylpyroglutamate has been used as a chiral auxiliary for α,β-unsaturated acids in Michael addition reactions. The conjugate addition of Grignard reagents to the amides in the presence of copper iodide, tetramethylene diamine (TMEDA) and trimethylsilyl chloride, proceeded with high yields and excellent stereoselectivities, yielding after hydrolysis enantiomerically pure β-substituted carboxylic acid derivatives.