α-Selenoenones could be employed as Z-allyl precursors in the chiral amine-catalyzed asymmetric conjugate addition of aldehydes. The obtained formal allylation product, a Z-olefin having a sulfonate leaving group, was employed as a synthetically useful chiral alkylating agent.
(−)-Erycibelline, the dihydroxynortropane alkaloid isolated from Erycibe elliptilimba Merr. et Chun., was synthesized using a cyclic nitrone as advanced intermediate, wherein the key step was the SmI2-induced intramolecular reductive coupling of cyclic nitrone with aldehyde which resulted in good yield and stereoselectivity.
The tungstate-catalyzed oxidation of N-alkyl-alpha-amino acids with hydrogen peroxide under phase-transfer conditions gives the corresponding nitrones in satisfactory yield.
Kinetic Resolution of Diiron Acyl Complexes—An Approach to Asymmetric Bicyclic -Lactams
Kinetic resolution is achieved in the reaction of racemic diiron complexes like 1 with the chiral nitrone (-)-2. Oxidative removal of the metal and reductive cleavage of the N-O bond provides β-amino acids. This sequence was used in the synthesis of β-amino acids as well as the corresponding β-lactams 4 (via 3).