Reactions with Protic Acids and Carbenium ions

1 Reactions with Protic Acids and Carbenium Ions. 

The hydrides R vSnII react with acids HX (e.g. HC1, carboxylic acids) to give R3SnX and H2, and the reactivity follows the sequence of acid strength (CH3C02H C1CH2C02H C12CHC02H C13CC02H).71 

The hydrostannation of aliphatic and aromatic aldehydes and ketones is catalysed by tributyltin triflate, Bu3Sn0S02CF3, acting as a Lewis acid, and this can be formed in situ from the reaction between triflic acid and tributyltin hydride.72 

In FS03H at -78 °C, the methyltin hydrides Me4 SnH react to give dihydrogen and the solvated cations Me4 SnH i+ which have been identified by NMR spectroscopy.73 If the solutions are then frozen to 77 K, the Mossbauer spectra show the presence of the stannyl fluorosulphonates Mc4 SnII OS()2F. 

The abstraction of hydride ion from R3SnH by Ph3C+ has been used as one approach for preparing cations R3Sn+ (Section 7-2)74 76 

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