Iodogen as a Novel Reagent for Diastereoselective Oxidation of Bisnaphthols under Green and Mild Condition

Iodogen, is a mild and effective reagent that is used mostly for the iodination of biological molecules. However, it is now introduced as a novel reagent for the oxidative cyclization of bisnaphthols to the corresponding Abel’s ketones (spirodienones). Notably, oxidation of bisnaphthols leads to the simultaneous formation of two chiral centers, and hence, two sets of diastereomers. Some oxidizing agents cause the formation of a mixture of these two sets, while others are specific for the distereoselective oxidation of bisnaphthols. Experiments show that only one set of these diastereomeres is selectively formed in high yield with iodogen. An advantage of this diastereoselctive oxidizing agent is that the reaction by-product can be separated and again converted into iodogen through a conventional chlorination reaction by trichloroisocyanuric acid.