FURTHER REACTIONS OF TERT-BUTYL 3-OXOBUTANTHIOATE AND TERT-BUTYL 4-DIETHYL-PHOSPHONO-3-OXOBUTANTHIOATE - CARBONYL COUPLING REACTIONS, AMINATION, USE IN THE PREPARATION OF 3-ACYLTETRAMIC ACIDS AND APPLICATION TO THE TOTAL SYNTHESIS OF FULIGORUBIN-A

The use of t-butyl-3-oxobutanthioate (1) and t-butyl 4-diethylphosphono-3-oxobutanthioate (2) for the preparation of homologated derivatives suitable for amination in the presence of silver (I) trifluoroacetate to afford the corresponding beta-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 beta-ketoamides were shown to be suitable precursors for 3-acyltetramic acids using a Dieckmann 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.