Recently, in our study toward the total synthesis of 7-deoxypancratistatin, 4 we needed to reductively cleave the N-O bond in the product resulting from a free radical addition to an oxime ether (Scheme 1). Specifically, we needed to reductively cleave the N-O bond of the trifluoroaceto-hydroxamic acid derivative 6. Despite the large number of efficient methods for N-O bond reduction, we encountered limitations of the more common procedures. Using our previously developed method involving reduction with AI(Hg) or Na(Hg) I° the desired transformation failed. Other methods such as hydrogenolysis sa also proved to be inefficient in the transformation of the trifluoroaceto-hydroxamic derivative 6 to the trifluoroacetamide.
