340161-41-3Relevant academic research and scientific papers
New auxiliaries for copper-catalyzed asymmetric Michael reactions: Generation of quaternary stereocenters at room temperature
Christoffers, Jens,Mann, Alexander
, p. 1014 - 1027 (2007/10/03)
Dialkyl amides of L-valine, L-isoleucine, and L-tert-leucine (2) are excellent chiral auxiliaries for the construction of quaternary stereocenters at ambient temperature. Enaminoesters 3, prepared from these auxiliaries 2 and Michael donors 1. undergo a copper-catalyzed asymmetric Michael reaction with methyl vinyl ketone (MVK, 4) to afford products 5 in 70-90% yield and 90-99% ee (enantiomeric excess). The exclusion of moisture or oxygen is not necessary. The auxiliaries 2 are readily available by standard procedures. After workup they can be recovered almost quantitatively.
