Biosynthesis of Tetronasin. Part 6. Preparation of Structural Analogues of the Diketide and Triketide Biosynthetic Precursors to Tetronasin.

Abstract The preparation of three analogues of the putative diketide biosynthetic precursor ( 2 ) and eight analogues of the putative triketide biosynthetic precursor ( 3 ) of the acyl tetronic acid ionophore tetronasin, as N-acetylcysteamine thioesters ( 4 ), ( 5 ), ( 6 ), ( 12 ), ( 13 ), ( 14 ), ( 15 ), ( 22 ), ( 23 ), ( 24 ) and ( 25 ) is described. Five examples are 19 F-labelled; a new, enantiospecific method for the creation of a fluorinated quaternary α-centre is presented.