3-chloro-3-methyl-2-butanone in ethanolic KOH at room temperature gave 3,3-dimethyl-5-aryltetrahydro-2-furanone as a major product. The reaction can be tentatively explained by the combination of Favorskii rearrangement and aldol reaction.
Anomeric hydroperoxides derived from 3,4,6-tri-O-benzyl-galactose and glucose were used for enantioselective epoxidation of naphthoquinone (12), chalcone (13), (E)-1,2-dibenzoyl ethylene (14) and (E)-iso-butyryl-phenyl ethylene (15). In the presence of sodium hydroxide, the epoxidations showed exceptional high asymmetric induction. The exchange of sodium by a potassium ion resulted in a low asymmetric
Remarkable effect of tris(4-fluorophenyl)phosphine oxide on the stabilization of chiral lanthanum complex catalysts. A new and practical protocol for the highly enantioselective epoxidation of conjugated enonesElectronic supplementary information (ESI) available: HPLC analysis of 2, 1H NMR data for 3 and 4, and crystal data for 5. See http://www.rsc.org/suppdata/ob/b4/b405882h/
A new and efficient chiral catalyst system, lanthanum–chiral BINOL–tris(4-fluorophenyl)phosphine oxide–cumene hydroperoxide, was developed for the epoxidation of α,β-unsaturated ketones thus providing the corresponding epoxy ketones with excellent enantioselectivities (up to >99% ee) in good to excellent yields at room temperature.
Stapled helical l-leucine-based heptapeptides were synthesized and used as catalysts for the enantioselective epoxidation of α,β-unsaturated ketones. All N-terminal free stapled peptides were successfully used as chiral catalysts. Among them, the use of H-hS3,7hS-10 gave epoxide products with high enantioselectivities of up to 99% ee. Furthermore, the dominant conformations of the N-terminal protected
The catalytic asymmetric epoxidation of enones using the La-BINOL-Ph(3)As=O complex generated from La(O-i-Pr)(3), BINOL, and Ph(3)As=O in a ratio of 1:1:1 is described herein. Using 1-5 mol % of the asymmetriccatalyst, a variety of enones, including a dienone and a cis-enone, were found to be epoxidized in a reasonable reaction time, providing the corresponding epoxy ketones in up to 99% yield and