Total synthesis of kaempferol and methylated kaempferol derivatives

Abstract

Kaempferol (1), a natural product from various plants, was synthesized in which the longest linear sequence is only seven steps in overall yields of 47% from commercially available 1,3,5-trimethoxybenzene (10). The methylated kaempferols 2-5 were also prepared by use of this concise synthetic methodology. The key transformations in this synthesis involved the I2 oxidative-promoting-cyclization and DDO oxidative hydroxylation. Several strategies to achieve 1 are provided.