Electrooxidation of certain naphthalene derivatives

Monatshefte fuer Chemie/Chemical Monthly (Impact Factor: 1.35). 05/2008; 139(5):513-519. DOI: 10.1007/s00706-007-0818-8

ABSTRACT Naphthalene and alkylnaphthalenes are electro-oxidized to give many products, of which 1,4-naphthoquinones and binaphthyls
are the most stable, especially in the case of substrates, which are not substituted in α-positions. On the other hand, α-substituted
naphthalenes give the respective naphthoquinols as the main products. Interestingly, 1,2-naphthoquinones are not separated
as products, instead, a fragmentation of one of the rings leads to oxidation products, in which the 1,2-bond in naphthalene
is broken to form dialdehydes or diketones. An anodic formation of binaphthyls is described, starting from alkyl-substituted
naphthalenes, dissolved in acetone-water (1:1 v/v) and using 0.1 M (CH3)4N(BF4) supporting electrolyte. Several isomeric binaphthyls were obtained depending on the substrates. The structure of the binaphthyls
formed is discussed based on molecular orbital calculations using the AM1 program. Cyclic voltammetric oxidation curves are
shown for naphthalene and three methyl derivatives.