12
views
0
recommends
+1 Recommend
0 collections
    0
    shares
      • Record: found
      • Abstract: found
      • Article: not found

      Direct synthesis of Z-alkenyl halides through catalytic cross-metathesis

      Read this article at

      ScienceOpenPublisherPMC
      Bookmark
          There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.

          Abstract

          Olefin metathesis has made a significant impact on modern organic chemistry, but important shortcomings remain: for example, the lack of efficient processes that can be used to generate acyclic alkenyl halides. Halo-substituted ruthenium carbene complexes decompose rapidly or deliver low activity and/or minimal stereoselectivity, and our understanding of the corresponding high-oxidation-state systems is very limited. In this manuscript, we show that previously unknown halo-substituted molybdenum alkylidene species are exceptionally reactive and are able to participate in high-yielding olefin metathesis reactions that afford acyclic 1,2-disubstituted Z-alkenyl halides. Transformations are promoted by small amounts of an in situ-generated catalyst with unpurified, commercially available and easy-to-handle liquid 1,2-dihaloethene reagents and proceed to high conversion at ambient temperature within four hours. Many alkenyl chlorides, bromides and fluorides can be obtained in up to 91 percent yield and complete Z selectivity. This method can be used to easily synthesize biologically active compounds and to perform the site- and stereoselective fluorination of other organic compounds.

          Related collections

          Most cited references 64

          • Record: found
          • Abstract: found
          • Article: not found

          Organic fluorine compounds: a great opportunity for enhanced materials properties.

          Interactions of "organic fluorine" have gained great interest not only in the context of crystal engineering, but also in the systematic design of functional materials. The first part of this tutorial review presents an overview on interactions known by organic fluorine. This involves π-π(F), C-F···H, F···F, C-F···π(F), C-F···π, C-F···M(+), C-F···C=O and anion-π(F) interactions, as well as other halogen bonds. The effect of the exchange of H vs. F is discussed by means of several examples and a short introduction to the young field of "fluorous" chemistry is given. The second part is dedicated to numerous applications of fluorine and fluorous interactions. It is shown how application of fluorination is used to enable a number of reactions, to improve materials properties and even open up new fields of research.
            Bookmark
            • Record: found
            • Abstract: not found
            • Article: not found

            Successful fluorine-containing herbicide agrochemicals

              Bookmark
              • Record: found
              • Abstract: found
              • Article: not found

              Z-Selective Catalytic Olefin Cross-Metathesis

              Alkenes are found in a great number of biologically active molecules and are employed in numerous transformations in organic chemistry. Many olefins exist as E or higher energy Z isomers. Catalytic procedures for stereoselective formation of alkenes are therefore valuable; nonetheless, methods for synthesis of 1,2-disubstituted Z olefins are scarce. Here we report catalytic Z-selective cross-metathesis reactions of terminal enol ethers, which have not been reported previously, and allylic amides, employed thus far only in E-selective processes; the corresponding disubstituted alkenes are formed in up to >98% Z selectivity and 97% yield. Transformations, promoted by catalysts that contain the highly abundant and inexpensive molybdenum, are amenable to gram scale operations. Use of reduced pressure is introduced as a simple and effective strategy for achieving high stereoselectivity. Utility is demonstrated by syntheses of anti-oxidant C18 (plasm)-16:0 (PC), found in electrically active tissues and implicated in Alzheimer’s disease, and the potent immunostimulant KRN7000.
                Bookmark

                Author and article information

                Journal
                0410462
                6011
                Nature
                Nature
                Nature
                0028-0836
                1476-4687
                6 February 2016
                24 March 2016
                24 September 2016
                : 531
                : 7595
                : 459-465
                Affiliations
                [1 ] Department of Chemistry , Merkert Chemistry Center, Boston College, Chestnut Hill, Massachusetts, 02467, USA.
                [2 ] Department of Chemistry , Massachusetts Institute of Technology , Cambridge, Massachusetts, 02139, USA.
                Author notes
                Correspondence and requests for materials should be addressed to A.H.H. ( amir.hoveyda@ 123456bc.edu ).
                Article
                NIHMS757164
                10.1038/nature17396
                4858352
                27008965

                Reprints and permissions information is available at npg.nature.com/reprintsandpermissions.

                Users may view, print, copy, and download text and data-mine the content in such documents, for the purposes of academic research, subject always to the full Conditions of use: http://www.nature.com/authors/editorial_policies/license.html#terms

                Categories
                Article

                Uncategorized

                Comments

                Comment on this article