187837-40-7Relevant articles and documents
Enantioselective epoxidation of α,β-unsaturated ketones catalyzed by stapled helical l-Leu-based peptides
Demizu, Yosuke,Yamagata, Nanako,Nagoya, Saori,Sato, Yukiko,Doi, Mitsunobu,Tanaka, Masakazu,Nagasawa, Kazuo,Okuda, Haruhiro,Kurihara, Masaaki
experimental part, p. 6155 - 6165 (2011/09/19)
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 stapled peptides R 3,7R-10 and hS3,7hS-10 were investigated by 1H NMR, IR, CD spectra, and X-ray crystallographic analysis. The peptide R3,7R-10 formed a right-handed (P) α-helix in solution and in the crystalline state, while hS 3,7hS-10 formed a right-handed (P) 310-helix in solution.
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 enones
Kino, Rie,Daikai, Kazuhiro,Kawanami, Toshio,Fumno, Hiroshi,Inanaga, Junji
, p. 1822 - 1824 (2007/10/03)
A new and efficient chiral catalyst system, lanthanumchiral BINOL-tris(4-fluorophenyl)phosphine oxidecumene hydroperoxide, was developed for the epoxidation of α,β-unsaturated ketones thus providing the corresponding epoxy ketones with excellent enantiose
A Class of C2 and Pseudo C2 Symmetric Ketone Catalysts for Asymmetric Epoxidation. Conformational Effect on Catalysis
Wang, Zhi-Xian,Miller, Susie M.,Anderson, Oren P.,Shi, Yian
, p. 6443 - 6458 (2007/10/03)
A class of C2 and pseudo C2 symmetric ketones with one fused ring at each side of the carbonyl group have been prepared from quinic acid and found to be effective catalysts for the asymmetric epoxidation of a variety of olefins. Electron deficient olefins such as enones can be efficiently epoxidized. Encouragingly good enantioselectivity is also obtained for the epoxidation of styrenes. The studies show that the ketone conformation plays an important role in the reactivity and selectivity of the catalyst.
