Seven-Step Stereodivergent Total Syntheses of Punicafolin and Macaranganin

The first total syntheses of punicafolin (1) and macaranganin (2) were achieved in seven steps, respectively, from commercial alpha-D-glucose. The characteristic features of the synthesis are (1) sequential site-selective introduction of the adequate galloyl groups into unprotected D-glucose by a catalyst-controlled manner and (2) stereodivergent construction of the 3,6-HHDP bridge by oxidative phenol coupling of a common intermediate via a ring-flipping process of the glucose core. Because no protective groups were used for glucose throughout the process, extremely short-step total syntheses of natural glycosides 1 and 2 (MW 938) were performed.

Automated summary

The total syntheses of punicafolin and macaranganin were achieved in seven steps each, starting from commercial alpha-D-glucose. The key features include sequential site-selective introduction of galloyl groups and stereodivergent construction of the 3,6-HHDP bridge without using protective groups for glucose, resulting in extremely short-step syntheses of natural glycosides with a molecular weight of 938.