The realm of aqueous organometallic catalysis incorporates many more reactions and catalysts than discussed in the preceeding chapters. However, these were not investigated in so much detail as, for instance, hydrogenation or hydroformylation; some of them are mentioned only here and there. An attempt is made to give a representative sample of these studies. At the end of this chapter, a few findings will be briefly mentioned, which do have some connection to aqueous organometallic catalysis in the sense we used this term throughout this book, but which perhaps could be best categorized as emerging techniques. . | Chapter 9 Miscellaneous catalytic reactions in aqueous media The realm of aqueous organometallic catalysis incorporates many more reactions and catalysts than discussed in the preceeding chapters. However these were not investigated in so much detail as for instance hydrogenation or hydroformylation some of them are mentioned only here and there. An attempt is made to give a representative sample of these studies. At the end of this chapter a few findings will be briefly mentioned which do have some connection to aqueous organometallic catalysis in the sense we used this term throughout this book but which perhaps could be best categorized as emerging techniques. Aqueous organometallic catalysis under traditional conditions In this part of the chapter we shall look at examples of catalytic isomerization hydration cyanation hydrocyanation hydrophosphination and animation reactions. Traditional conditions refer to ranges of temperature and pressure within which water behaves as we are used to it normally it forms a highly polar liquid phase capable of dissolving electrolytes and polar substances. Under such conditions water is a poor solvent for nonpolar organic compounds which -with appropriate organic solvents- allows the use of aqueous-organic biphasic media for organometallic catalysis. A guide to the literature of these studies is found in Table . Isomerization is a frequent side-reaction of catalytic transformations of olefins however it can be a very useful synthetic method as well. One of the best-known examples is the enantioselective allylamine enamine isomerization catalyzed by Rh - or S -BINAP COD which is the crucial step in the industrial synthesis of L-menthol by Takasago 42 265 266 Chapter 9 performed under unhydrous conditions . Especially valuable feature of isomerizations is in that all atoms of the starting compound are incorporated into the product respresenting a 100 atom economy. Table . Miscellaneous catalytic reactions in .
