From Bis- Phenylthio- Acetals

Hie anions of 68 and 79 are then useful acyl anion equivalents, but in natural product syntheses they are far less popular than reagents containing two sulphur atoms54, particularly dithians55. The chemistry of dithians, e. g. 86 and 87 has been well explored and they have been used in the synthesis of many natural products . The synthesis56 of the Douglas-Fir tussock moth sex pheromone 88 is an example of the way a dithian 86 acts as an acyl anion equivalent in ketone syntheses. 

The required ketone 91 is formed almost intantaneously the other product is diphenyl disulphide. We have some evidence57 for a mechanism involving PhS migration for this reaction. As examples, ketones 92 (64% yield) and 93 (88%) can be made this way57.  

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