Hypervalent Iodine Iodinative Decarboxylation Of Cubyl And Homocubyl Carboxylic Acids

Abstract

The hypervalent iodine oxidative decarboxylation of homocubyl and cubyl mono- and di-carboxylic acids is reported; the carboxylic acid is treated with PhI(OAc)2CC14-I2 under irradiation conditions and 80-90% of the derived iodo compound is obtained. Systematic functionalization of cubane is an important synthetic goal. The two main methods of cubane synthesis involve sequential Favorskii ring contractions to yield first a homocubyl carboxylic acid, and theh after a second Favorskii reaction, a 1,41,2 or 1,33 cubyl dicarboxylic acid. As a consequence of this synthetic procedure the carboxy group is a logical starting functionality for subsequent synthetic transformation in the cubyl ring system. The carboxy group has been converted ,into a nitro group in the synthesis of 1,4-dinitrocubane4 and halogenodecarboxylation has been effected.596 In a basically different approach Eaton et al., used ortho-lithiation of the der td carboxamide etc a site for ortho-iodination.7 Introduction of an iodo group onto the cubyl system is especially desirable because hypervalent iodine synthetic methodology may be employed in order to effect displacement reactions. This scheme has been successfully applied by Eaton et al.8 in tim cubyl system for R-IC12+ R-C1 R-I(OAC)2+ R-OAc where R=1- iodo-2-N,N-di-isopropylcarbox-amido-5-methylcubane.