Optically active arsines resolution

Mori, K., and Toda, F. (1990) Optical Resolution of Arsine Oxides by Complexation with Optically Active [1,1 -Binaphthyl]-2,2 -diol, Bull. Chem. Soc. Jpn., 63, 2127-2128. 

Tetrachloroauric(III) acid in aqueous ethanol reacted with an excess of the phosphine-arsine undergoing reduction and chelation to give the cation, LXVII, precipitated as the colorless, highly stable iodide. The 4-coordinate aurous atom in this compound has the tetrahedral configuration, and attempts were made to resolve the cation into optically active forms. Fractional recrystallization of eight salts having different optically-active anions failed to give any indication of resolution. 

Relatively few applications of optically active tertiary arsines to asymmetric synthesis have been reported by comparison with the extensive work with phosphines . Authoritative accounts of the synthesis and stereochemistry of compounds of Group V elements are available other reviews cover the subject up until 1979 . For general treatments of organoarsenic chemistry up until 1976, including optically active compounds, two important works are available . Of related interest is an article on stereochemical aspects of phosphorus chemistry and another published in this series on optically active phosphines preparation, uses and chiroptical properties . On matters concerning the intricacies of resolutions work, the reader should consult Reference 21, especially Chapter 7, which is entitled Experimental Aspects and Art of Resolutions. 

The discoverj( of the stereoselective biomethylation of a prochiral arsinic acid by a microorganism opens up an exdting new route to optically active tertiary arsines. Numerous microorganisms reductively methylate arsenic(V) compounds . The biological synthesis of (+)-126 by Scopulariopsis brevicaulis was described in 1936. At that time, however, it was not recognized that simple tertiary arsines chiral at arsenic were configurationally stable and amenable to optical resolution. 

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