Enantioselective Photocycloaddition of 3‑Hydroxyflavones: Total Syntheses and Absolute Configuration Assignments of (+)-Ponapensin and (+)-Elliptifoline

We have previously reported development of biomimetic,
asymmetric
[3 + 2] photocycloadditions between 3-hydroxyflavones and cinnamate
dipolarophiles to access (−)-rocaglamide and related natural
products. Herein, we describe enantioselective syntheses of aglain
cycloadducts leading to the first total syntheses and absolute configuration
assignments of the aglain natural products (+)-ponapensin
and (+)-elliptifoline.