Organozinc Compound - Synthesis

Synthesis

Several general methods exist for the generation of organozinc compounds.

  • Oxidative addition. The original diethylzinc synthesis by Frankland was an oxidative addition of iodoethane to zinc metal with hydrogen gas as a "protective" blanket (this reaction is called the Frankland synthesis). The reactivity of zinc metal is increased in so-called Rieke zinc obtained by reduction of zinc chloride by potassium metal.
2RI + 2Zn → ZnR2 + ZnI2
  • Halogen zinc exchange. Two main halogen zinc exchange reactions are iodine zinc exchange and boron zinc exchange. The first step in the second procedure is hydroboration of an alkene:
  • Transmetalation. In a typical transmetalation, diphenylmercury reacts with zinc metal to diphenylzinc and metallic mercury in diethyl ether. Unfortunately, this reaction is slow, taking two weeks.
  • Organozinc compounds can be obtained directly from zinc metal:
In this method zinc is activated by the action of 1,2-dibromoethane and trimethylsilyl chloride. A key ingredient is lithium chloride which quickly forms a soluble adduct with the organozinc compound thus removing it from the metal surface.

Read more about this topic:  Organozinc Compound

Famous quotes containing the word synthesis:

    “It is not easy to construct by mere scientific synthesis a foolproof system which will lead our children in a desired direction and avoid an undesirable one. Obviously, good can come only from a continuing interplay between that which we, as students, are gradually learning and that which we believe in, as people.”
    —Erik H. Erikson (20th century)

    “In order to begin an analysis, there must already be a synthesis present in the mind.”
    —Johan Huizinga (1872–1945)

    “The invention of photography provided a radically new picture-making process—a process based not on synthesis but on selection. The difference was a basic one. Paintings were made—constructed from a storehouse of traditional schemes and skills and attitudes—but photographs, as the man on the street put, were taken.”
    —Jean Szarkowski (b. 1925)