A newsyntheticmethod of 3-acyltetronic acidderivatives from the corresponding 3-bromo compound via lithiation with n-BuLi followed either by acylation with acid chloride or better by first reacting with aldehyde and then subsequent oxidation with active MnO2 is described. A revised structure for aspertetronin A(gregatin A) was presented based on the synthesis of the proposed structure and spectral
Vinylic carbanions in synthesis. Novel syntheses of iso-gregatin B, iso-aspertetronin A and related O-methyl tetronic acids
作者:Nicholas G. Clemo、Gerald Pattenden
DOI:10.1016/s0040-4039(00)86897-5
日期:1982.1
Reaction between the octadienone (8) and the vinylic carbanion (6) derivedfrom (5) leads, in one step, to the O-methyl tetronic acid (9). Metallation of (9), followed by treatment of the resulting α-vinylic carbanion with methyl acetate and with methyl -butenoate then gives the acylated O-methyl tetronic acids (12) and (14) respectively which are shown to be enol ether isomers of the natural products