Photo-Arbuzov reaction

The Michaelis-Arbuzov reaction may be photoinitiated with appropriate sub- strates such as tetrahalomethanes and aryl iodides suitable phosphites undergo photo-Arbuzov rearrangement (see below). 

The photo-Arbuzov rearrangement of allylic52 and benzylic53 phosphites has been developed by Bentrude and co-workers, see, for example, Scheme 12. These reactions are completely regioselective for the benzyl and allyl groups and have been employed in synthesis (the requisite phosphites being obtained by standard methods).54... 

Whilst arguably, the formaldehyde condensation reactions in the preceding section are, under acidic conditions, electrophilic in type, a considerably wider range of compounds result from the commercially available C4, Cg, and Cg alkylphenols with a variety of reactants in other electrophilic substitution reactions. Thus 2,6-di-tert-butylphenol condensed with formaldehyde in hydrochloric acid gives 3,5-di-tert-butyl-4-hydroxybenzyl chloride which can be utilised in an Arbuzov reaction with trialkylphosphites to afford the dialkyl phosphonate depicted (ref. 80). The diethyl ester (Irganox 1222, Ciba-Geigy Ltd.) in this series is a significant stabiliser for polyester fibres in the prevention of photo and oxidative deterioration. 

This reaction has been extensively modified. Besides the ruthenium-catalyzed, metal-centered radical or photo-Arbuzov rearrangements as described earlier, alkyl halides have been replaced by metal halides (e.g., NiC ), trimethylsilyl chloride (TMSCl), and organometallics. 

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