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Hydrofunctionalization
A hydrofunctionalization reaction is the addition of hydrogen and another univalent fragment (X) across a carbon-carbon or carbon-heteroatom multiple bond. Often, the term ''hydrofunctionalization'' without modifier refers specifically to the use of the covalent hydride (H-X) as the source of hydrogen and X for this transformation. If other reagents are used to achieve the net addition of hydrogen and X across a multiple bond, the process may be referred to as a ''formal hydrofunctionalization''. For terminal olefins (or acetylenes), the regioselectivity of the process can be described as Markovnikov (addition of X at the substituted end) or anti-Markovnikov (addition of X at the unsubstituted end). Catalysts are frequently employed to control the chemo-, regio-, and stereoselectivity of hydrofunctionalization reactions. Examples Some of the better known classes of hydrofunctionalization reactions include the following: * Hydroboration * Hydrosilylation * Hydrometalation (in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
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Hydroalkoxylation
Hydroalkoxylation is a chemical reaction that combines alcohols with alkenes or alkynes. The process affords ethers. The reaction converts alkenes to dialkyl or aryl-alkyl ethers: :R'OH + RCH=CH2 → R'OCH(R)-CH3 Similarly, alkynes are converted to vinyl ethers: :R'OH + RC≡CH → R'OC(R)=CH2 As shown, the reaction follows the Markovnikov rule. The process exhibits good atom-economy in the sense that no byproducts are produced. The reaction is catalyzed by bases and also by transition metal complexes. Usually symmetrical ethers are prepared by dehydration of alcohols and unsymmetrical ethers by the Williamson ether synthesis The Williamson ether synthesis is an organic reaction, forming an ether from an organohalide and a deprotonated alcohol (alkoxide). This reaction was developed by Alexander Williamson in 1850. Typically it involves the reaction of an alkoxide ... from alkyl halides and alkali metal alkoxides.Wilhelm Heitmann, Günther Strehlke, Dieter Mayer "Ethers, Ali ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |