Two-carbon ring expansion of cyclobutanone skeletons by nickel-catalyzed intermolecular alkyne insertion
摘要:
The reaction of cyclobutanone with an alkyne in the presence of a nickel(0) catalyst formally achieves intermolecular alkyne insertion between the carbonyl carbon and the a-carbon of a cyclobutanone, providing a six-membered carbocyclic skeleton. (c) 2006 Elsevier Ltd. All rights reserved.
Palladium-Catalyzed Diastereo- and Enantioselective Wagner−Meerwein Shift: Control of Absolute Stereochemistry in the C−C Bond Migration Event
作者:Barry M. Trost、Jia Xie
DOI:10.1021/ja7111299
日期:2008.5.1
Inducing absolute stereochemistry in Wagner-Meerwein shifts was examined in a ring expansion protocol. Initiated by generation of a pi-allylpalladium intermediate by hydropalladation of allenes, the ring expansion of allenylcyclobutanol substrates proceeded with excellent diastereo- and enantioselectivities. The results demonstrate that, during the C-C bond migration process, our chiral catalysts can control the stereochemistry of both the pi-allylpalladium intermediate and the corresponding migration bond. Moreover, the stereochemical outcome of the reaction can be rationalized very well with the working model of the chiral catalyst. The method provides an efficient way to synthesize highly substituted cyclopentanones with an alpha-chiral O-tertiary center which has various synthetic applications.
Substitution of chlorocyclobutanones with xanthate salts. The remarkable effect of added base
作者:Rama Heng、Béatrice Quiclet-Sire、Samir Z. Zard
DOI:10.1016/j.tetlet.2009.03.133
日期:2009.7
The substitution reaction of chlorocyclobutanones with dithiocarbonates (xanthates) is greatly accelerated by the addition of a mild base such as DABCO or DBU. (C) 2009 Elsevier Ltd. All rights reserved.
Two-carbon ring expansion of cyclobutanone skeletons by nickel-catalyzed intermolecular alkyne insertion
The reaction of cyclobutanone with an alkyne in the presence of a nickel(0) catalyst formally achieves intermolecular alkyne insertion between the carbonyl carbon and the a-carbon of a cyclobutanone, providing a six-membered carbocyclic skeleton. (c) 2006 Elsevier Ltd. All rights reserved.
Adler, Roger W.; Allen, Paul R.; Anderson, Kevin R., Journal of the Chemical Society. Perkin transactions II, 1998, # 10, p. 2083 - 2108
作者:Adler, Roger W.、Allen, Paul R.、Anderson, Kevin R.、Butts, Craig P.、Khosravi, Ezat、et al.