Copper-catalyzed diastereo- and enantioselective desymmetrization of cyclopropenes: Synthesis of cyclopropylboronates

This document is the accepted manuscript version of a Published Work that appeared in final form in Journal of American Chemical Society 136.45, copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see DOI: 10.1021/ja510419zA novel Cu-catalyzed diastereo- and enantioselective desymmetrization of cyclopropenes to afford nonracemic cyclopropylboronates is described. Trapping the cyclopropylcopper intermediate with electrophilic amines allows for the synthesis of cyclopropylaminoboronic esters and demonstrates the potential of the approach for the synthesis of functionalized cyclopropanesWe thank the European Research Council (ERC-337776) and MINECO (CTQ2012-35957) for financial support. M. T. and A. P. thank MICINN for RyC and JdC contract

Synthesis of nitrogen-substituted methylenecyclopropanes by strain-driven overman rearrangement of cyclopropenylmethyl trichloroacetimidates

Nitrogen-substituted methylenecyclopropanes have been prepared by a strain-driven Overman rearrangement of cyclopropenylmethyl trichloroacetimidates. The reaction proceeds at room temperature and without the need of a transition-metal catalyst. Furthermore, it has been shown that C-3-substituted cyclopropenylmethyl trichloroacetimidates undergo a hydrolytic ring-opening reaction to form allenylcarbinols

Microbial Inactivation by Cupric Ion in Combination with H2O2: Role of Reactive Oxidants

The cupric ion mediated inactivation of Escherichia coli was enhanced by the presence of hydrogen peroxide (H2O2), with increasing inactivation efficacy observed in response to increasing concentrations of H2O2. The biocidal activity of the Cu(II)/H 2O2 system is believed to result from the oxidative stress caused by reactive oxidants such as the hydroxyl radical (•OH), cupryl species (Cu(III)), and the superoxide radical (O2 •-), which are produced via the catalytic decomposition of H2O2. In E. coli cells treated with Cu(II) and H 2O2, the intracellular level of •OH and Cu(III) increased significantly, leading to complete disruption of cell membranes. On the basis of experimental observations made using an •OH scavenger, copper-chelating agents, and superoxide dismutase, it is concluded that Cu(III) is the predominant species responsible for the death of E. coli cells. It was also found that the production of Cu(III) was promoted by the reactions of copper with intracellular O2 •-. MS2 coliphage was found to be even more susceptible than E. coli to the oxidative stress induced by the Cu(II)/H2O2 system.close1