Stereoselective syntheses of (-)-podorhizol lignan and its derivatives: Erythro and threo preferential aldol condensation of potassium enolate from γ-butyrolactone with alkoxybenzaldehyde

Article abstract of DOI:10.1271/bbb.63.1453

(-)-Podorhizol (1) was stereoselectively synthesized by erythro preferential aldol condensation of 3,4,5-trimethoxybenzaldehyde with potassium enolate from (+)-(R)-3-(3,4-methylenedioxybenzyl)-4-butanolide (2) (erythro: threo=85:15). Erythro selectivity was observed in the aldol condensation of many alkoxybenzaldehydes with potassium enolate from (+)-γ-butyrolactone 2. However, benzaldehydes having methoxy groups at both the 2 and 6 positions gave threo selectivity in the aldol condensation with potassium enolate from (+)-γ-butyrolactone 2.