Regioselective Pd-Catalyzed Synthesis and Application of 3-Methyl-5-bromo-2-pyrone toward Keto-phomactin A

An efficient one-step synthetic protocol for 3-methyl-5-bromo-2-pyrone was developed using the C3-selective Pd-catalyzed coupling reaction of 3,5-dibromo-2-pyrone with Me3Al−dimethylaminoethanol complex. A subsequent seven-step reaction sequence provided a cyclohexenyl bromide, which served as the key intermediate for the synthesis of the keto analogue of phomactin A, in 31% overall yield.