Helical peptide foldamer catalyzed Michael addition reactions of nitroalkane or dialkyl malonate to α,β-unsaturated ketones are reported along with the mechanistic considerations of the enantio-induction. A wide variety of α,β-unsaturated ketones, including β-aryl, β-alkyl enones, and cyclic enones, were found to be catalyzed by the helical peptide to give Michael adducts with high enantioselectivities
Chalk it up as a “Sc”andal: The asymmetricconjugateaddition of chalcone and “cinnamone” derivatives to nitromethane has been realized by using a simple and efficient scandium(III)–N,N′‐dioxide complex as the catalyst (see scheme). In the presence of 2–5 mol % catalyst loading, the corresponding products were formed in excellent yields (up to 99 %) and enantioselectivities (up to>99 % ee).