Triflic acid hydrogen formation

On the other hand polysilylalkynes with phenyl or allyl substituents are converted with triflic acid into polymeric alkynylsilyltriflates. These polymers react with many acidic element hydrogen compounds or lithium element compounds with formation of silicon element bonds. Thus we found an easy approach to numerous new functional substituted alkynes [12], Eq.(9) shows selected examples of this reaction type. 

Subsequently McMurry and Lectka" successfully designed an appropriate system to observe stoichiometric hydrogen formation with liquid superacidic triflic acid. They found that when a highly stable carbocation is formed, weaker acids may be applied in protolysis, eliminating the need to use conjugate superacids. Indeed, when the bicyclic compound [Eq. (6.14)] was treated with triflic acid, 90% of the theoretical amount of hydrogen evolved. 

In the course of investigating the general utility of urea-hydrogen peroxide, the formation of 4-oxahomoadamantane was observed when adamantane was reacted with the UHP-triflic acid system. A typical procedure involved mixing triflic acid (10 mL) with a solution of adamantane (0.545 g = 0.004 mol) dissolved in 25 mL CH2CI2 to which urea-hydrogen peroxide (0.760 g = 0.008 mol) is slowly added. The addition of the UHP was performed at -15 to -5 °C slowly warming to 5 °C and then allowed to react for two hours after addition is complete. The product was then quenched with ice water followed by extraction with diethyl ether/dichloromethane and evaporation of solvent to... 

Sodium borohydride in excess of triflic acid at low temperature provides" a highly efficient reductive superacid system, which was found effective for the reductive superacid isomerization of unsaturated polycyclic precursers to cage hydrocarbons in high yields (equation 25). The key to the success of the ionic hydrogenation system appears to be due to the in situ formation of boron tris(triflate), a highly superacidic Lewis acid. 

Let us first take a solution of e.g. triflic add (HT) in CH2CI2 and then add a nucleophile. In CH2CI2 hydrogen-bmded associates of acid and free add are involved in multiple equilibria. Ionization proceeds with formation of nucleophilic anion, which bonds by l rdiogen bondii to the free add (one or nwre molecules of acid are involved) ... 

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