Electrochemical oxidation of α-alkoxystannanes

A New Route to Enol Ethers

“…11 The related formation of acetals by electrochemical oxidation of alkoxymethylstannanes in the presence of alcohols was also reported. 12 As for acceleration of the reaction with lithium bromide, we tentatively assume that it is attributable to increase in solubility of CuBr 2 through the formation of a certain cuprate 13 or generation of a highly coordinated organotin species from the stannylthioacetal 7 which facilitates its oxidation with CuBr 2 . 14…”

Intramolecular acceleration effect of a tosylamide group on the electrochemical oxidation of N-α-silylalkyl amides

“…Thus, the tosylamide moiety exhibits nucleophilicity in the presence of trifluoroethanol in the electrochemical oxidation of 3 to give 7. 15 These results suggest that in the cation radical intermediate, the tosylamide moiety attacks the intramolecular positively charged silyl atom to assist the carbon-silyl bond cleavage resulting in an iminium radical, and the tosylamide moiety traps the silyl cation released in the reaction process, so that the nucleophilicity of the tosylamide moiety is decreased (Scheme 1). In the presence of trifluoroethanol, which is more silanophilic but less nucleophilic than the tosylamide moiety, the silyl cation trapped by the tosylamide moiety is removed by trifluoroethanol, and the tosylamide moiety recovers its nucleophilicity to yield 7.…”

Redox selective reactions of organo-silicon and -tin compounds

“…The introduction of a stannyl group on the carbon adjacent to the heteroatom decreases the oxidation potential significantly (Table 4). 21 The effect of tin is attributed to the interaction between the C᎐Sn σ orbital and the non-bonding p orbital of the heteroatom, increasing the HOMO level which in turn favors electron transfer. The variation of the HOMO levels of the model compounds H 3 SnCH 2 OH and H 3 SnCH 2 SH with torsion angle is shown in Fig.…”

“…The reaction pattern of the oxidation of stannyl-substituted heteroatom compounds is quite similar to that of silylsubstituted heteroatom compounds. 21 Electrochemical oxidation leads to selective cleavage of the C᎐Sn bond and the introduction of nucleophiles on the carbon.…”