Palladium-Catalyzed Asymmetric Ring Expansion of Allenylcyclobutanols: An Asymmetric Wagner−Meerwein Shift
作者:Barry M. Trost、Jia Xie
DOI:10.1021/ja0602501
日期:2006.5.1
In this study, we developed a palladium-catalyzed atom economic asymmetricWagner-Meerweinshift of allenylcyclobutanol substrates. It is an excellent method for creating functionalized cyclopentanones with an alpha-chiral O-tertiary center by ring expansion of allenylcyclobutanols. This reaction was initiated by hydropalladation and afforded excellent enantioselectivity as well as atom economy. This
Oxidative rearrangement of 1,1-disubstituted alkenes to ketones
作者:Qiang Feng、Qian Wang、Jieping Zhu
DOI:10.1126/science.adg3182
日期:2023.3.31
to the ring expansion of highly strained methylene cyclobutane derivatives. Herein, we report a solution to this synthetic challenge by designing a Pd II /Pd IV catalytic cycle incorporating a 1,2-alkyl/Pd IV dyotropic rearrangement as a key step. This reaction, compatible with a broad range of functional groups, is applicable to both linear olefins and methylenecycloalkanes, including macrocycles.
A Stereospecific Alkene 1,2‐Aminofunctionalization Platform for the Assembly of Complex Nitrogen‐Containing Ring Systems
作者:Yuxiang Zhu、Matthew J. S. Smith、Wenbin Tu、John F. Bower
DOI:10.1002/anie.202301262
日期:——
activated N-Boc hydroxylamines triggers aminofunctionalization-based polycyclizations of tethered alkenes. The processes involve intramolecular stereospecific aza-Prilezhaev alkene aziridination in advance of stereospecific C−N cleavage by a pendant nucleophile. Using this approach, a wide range of alkene anti-1,2-difunctionalizations can be achieved.
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.