In vitro enzymatic oxidation of a fluorine‐tagged sulfido substrate analogue: a 19 F NMR investigation

1 H‐decoupled 19 F NMR has been used to monitor the highly regioselective oxidation of a fluorine‐tagged thia‐fatty acid derivative by castor stearoyl‐ACP Δ 9 desaturase. The major enzymatic product, after reductive work‐up, was identified as 9‐fluoro‐1‐nonanol. This compound could be easily distinguished from substrate and a 9‐sulfoxy by‐product on the basis of its 19 F NMR chemical shift and spiking experiments using authentic standards. Structural assignment of the cleavage product was confirmed by GC‐MS analysis of the enzymatic products. Copyright © 2006 John Wiley & Sons, Ltd.