Stereoselective Synthesis of Lignans of Three Structural Types from a Common Intermediate, Enantioselective Synthesis of (+)-Yangambin

Enantioselective total synthesis of furofuran lignans via Pd-catalyzed asymmetric allylic cycloadditon of vinylethylene carbonates with 2-nitroacrylates

Herein, a practical and efficient approach to tetrahydrofurans with three-stereocenters has been developed through Pd-catalyzed asymmetric allylic cycloaddition of vinylethylene carbonates (VECs) with 2-nitroacrylates under mild conditions. By using this asymmetric catalytic reaction as a key step, several furofuran lignans with stereodivergency have been effectively synthesized through 5- or 6-step sequences from readily available starting materials.

A sterically encumbered photoredox catalyst enables the unified synthesis of the classical lignan family of natural products

Herein, we detail a unified synthetic approach to the classical lignan family of natural products that hinges on divergence from a common intermediate that was strategically identified from nature's biosynthetic blueprints. Efforts toward accessing the common intermediate through a convergent and modular approach resulted in the discovery of a sterically encumbered photoredox catalyst that can selectively generate carbonyl ylides from electron-rich epoxides. These can undergo concerted [3 + 2] dipolar cycloadditions to afford tetrahydrofurans, which were advanced (2-4 steps) to at least one representative natural product or natural product scaffold within all six subtypes in classical lignans. The application of those synthetic blueprints to the synthesis of heterolignans bearing unnatural functionality was demonstrated, which establishes the potential of this strategy to accelerate structure-activity-relationship studies of these natural product frameworks and their rich biological activity.