Further Reactions of t-Butyl 3-Oxobutanthioate and t-Butyl 4-Diethylphosphono-3-oxobutanthioate: Carbonyl Coupling Reactions, Amination, Use in The Preparation of 3-Acyltetramic Acids and Application to The Total Synthesis of Fuligorubin A.

Article abstract of DOI:10.1016/S0040-4020(01)88210-7

Key words: Acyltetramic acid; Phosphonate; Wadsworth-Emmons; Dieckmann cyclisation; Fuligorubin A. Abstract: The use of t-butyl-3-oxobutanthioate (1) and t-butyl 4-diethylphosphono-3-oxobuthanthioate (2) for the preparation of homologated derivatives suitable for amination in the presence of silver(I) trifluoroacetate to afford the corresponding β-ketoamides is discussed.In particular Wadsworth-Emmons coupling reactions of (2) with various carbonyl compounds gave good yields of E-substituted products.Many of the β-ketoamides were shown to be suitable precursors for 3-acyltetramic acids using a Dieckman cyclisation with tetra-n-butyl ammonium fluoride as the cyclising base.These new reactions were applied to the total synthesis of the polyene 3-acyltetramic acid fuligorubin A.