Synthesis of 2-Nickela(II)oxetanes from Nickel(0) and Epoxides: Structure, Reactivity, and a New Mechanism of Formation
作者:Addison N. Desnoyer、Eric G. Bowes、Brian O. Patrick、Jennifer A. Love
DOI:10.1021/jacs.5b06735
日期:2015.10.14
frequently invoked as reactive intermediates in catalytic reactions of epoxides using nickel, but have never been isolated or experimentally observed in these transformations. Herein, we report the preparation of a series of well-defined nickelaoxetanes formed via the oxidative addition of nickel(0) with epoxides featuring ketones. The stereochemistry of the products is retained, which has not yet been reported
Catalytic Asymmetric Epoxidation of 2-Cyclopentenones
作者:Anna Lee、Corinna M. Reisinger、Benjamin List
DOI:10.1002/adsc.201200072
日期:2012.6.18
The first highly efficient asymmetricepoxidation of 2‐cyclopentenones has been developed. Using a newly designed and readily available Cinchona amine catalyst, 2‐cyclopentenones are reacted with hydrogen peroxide to give the corresponding epoxycyclopentanones in high yields and excellent enantioselectivities.
A series of 2-aryl-and arylmethyl-3-dialkylphenylsilyl cycloalkanones have been prepared and resolved. The pure enantiomers were reduced to the corresponding cycloalkane derivatives. These were used for the in situ generation of enantiopure cycloalkylsilyl triflimides by protodesilylation with bis( trifluoromethanesulfonyl) imide. The association of a bulky leaving group with a silicon atom carrying large substituents was again shown to favour the complexation of silicon with carbonyl groups: all these trialkylsilyl triflimides showed a high catalytic activity for Diels -Alder reactions. Enantiomeric excesses up to 59% were observed. This is the highest enantioselectivity ever observed for a Diels-Alder reaction catalysed by a silicon Lewis acid. (c) 2007 Elsevier Ltd. All rights reserved.
KANG, JAHYO;KIM, DO HYUNG;LEE, JAE HYOUNG;RIM, JONG GIL;YU, BONG YOON;KYU+, J. ORG. CHEM., 55,(1990) N1, C. 5555-5558
作者:KANG, JAHYO、KIM, DO HYUNG、LEE, JAE HYOUNG、RIM, JONG GIL、YU, BONG YOON、KYU+