Reduction by a Model of NAD(P)H. 45. Mechanism for the Dediazoniation of Arenediazonium Salts Initiated by One-Electron Transfer from an NAD(P)H Model

Article abstract of DOI:10.1021/jo00179a024

Arenediazonium fluoroborates, ArN2BF4 (1a, Ar=p-CH3C6H4; 1b, Ar=p-BrC6H4; 1c, Ar=p-NO2C6H4) react with an NAD(P)H model, N-benzyl-1,4-dihydronicotinamide (BNAH), in methanol, giving the corresponding reduction products ArH (2).The stoichiometry for the starting materials and reduction products clearly indicates that this reduction involves a radical-chain path initiated by BNAH.The mechanism is supported by the effect of spin-trapping agents on the yields of the products.From the results from experiments with methanol-d₄, we have found that under a nitrogenatmosphere, the radical chain is more favorable in the order 1a < 1b < 1c, which is the same as the order in the thermal dediazoniation of 1 in acidic methanol.The results presented here provide direct evidence for a one-electron transfer mechanism for reduction with an NAD(P)H model.