A novel palladium-catalyzed alkene diacetoxylation with dioxygen (O-2) as both the sole oxidant and oxygen source is developed, which was identified by O-18-isotope labeling studies. Control experiments suggested that bis(pinacolato)diboron (B(2)pin(2)) played a dominant intermediary role in the formation of a C-O bond. This method performed good functional group tolerance with moderate to excellent yields, which could be successfully applied to the late-stage modification of natural products. Furthermore, an atmospheric pressure of dioxygen enhances the practicability of the protocol.
Palladium-Catalyzed Olefin Dioxygenation
作者:Yang Li、Datong Song、Vy M. Dong
DOI:10.1021/ja711029u
日期:2008.3.1
A general method for the vicinal dioxygenation of olefins was developed using cationic Pd diphosphine complexes as the catalysts and Phl(OAC)(2) as the terminal oxidant. In comparison to known Pd-catalyzed vicinal oxidations, this method is suitable for a broad range of olefins in both inter- and intramolecular reactions. An (18)O-labeling experiment provides insight into the mechanism of this transformation which presumably involves Pd(II)/Pd(IV) intermediates.
Criegee, Justus Liebigs Annalen der Chemie, 1930, vol. 481, p. 263,286
作者:Criegee
DOI:——
日期:——
Metal-Free, Organocatalytic <i>Syn</i> Diacetoxylation of Alkenes
作者:Wenhe Zhong、Shan Liu、Jun Yang、Xiangbao Meng、Zhongjun Li
DOI:10.1021/ol301311e
日期:2012.7.6
A novel method for the organocatalytic syn diacetoxylation of alkenes has been developed using aryl iodides as efficient catalysts. A broad range of substrates, including electron-rich as well as electron-deficient alkenes, are smoothly transformed by the new procedure, furnishing the desired products in good to excellent yields with high diastereoselectivity (up to >19:1 dr).
Ruthenium- and lipase-catalyzed DYKAT of 1,2-diols: an enantioselective synthesis of syn-1,2-diacetates
Regio- and stercoselective lipase-catalyzed kinetic resolutions were investigated for some unsymmetrical, secondary/secondary syn-diols. Candida antarctica lipase B-catalyzed transesterifications of a few aryl/alkyl- and alkyl/alkyl 1,2-diols were coupled in one-pot for efficient ruthenium-catalyzed epimerization and intramolecular acyl migration to give a dynamic kinetic asymmetric transformation (DYKAT) affording enantioenriched (ee up to > 99%) syn-diacetates as the main diastereomers (sywanti similar to 2:1 to 10:1). (c) 2006 Elsevier Ltd. All rights reserved.