Manganese thiophene, reactions with

Benzo[6]thiophene aldehydes have also been prepared by oxidation of the corresponding primary alcohol with fer -butyl chromate,518 nitric acid,518 or manganese dioxide,337,565 and by reaction of the... 

Catalytic reduction of thiopyrylium salts under forcing conditions yields tetrahy-drothiopyrans, but oxidation with manganese dioxide of the unsubstituted thiopyrylium cation (first obtained by Pettit [100]) affords thiophene-2-carbaldehyde in a reaction without analogy to pyrylium salts [101], Like a- and y-benzylic positions in pyrylium salts, methyl(ene) groups of alkyl substituents in thiopyrylium cations are usefully acidic and as such the corresponding anhydrobases may be trapped by various nucleophiles. 

Jt-Coordination of benzo[3]thiophene, dibenzothiophene, and 2,5-dimethylthiophene activates the C-S bonds toward metal insertion. Thus Pt(PPh3)3 fails to react with 2,5-dimethylthiophene. But if the latter is 77 -coordinated with manganese tricarbonyl, the reaction takes place at room temperature to give 239 <20010M1259>. 

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