Diels–Alder Reactions of α‑Amido Acrylates with <i>N</i>‑Cbz-1,2-dihydropyridine and Cyclopentadiene

Thermal Diels–Alder reactions of α-amido acrylates with <i>N</i>-Cbz-1,2-dihydropyridine and cyclopentadiene have been explored to investigate the factors influencing the <i>endo/exo</i> selectivity. For the dihydropyridine, steric factors allowed the diastereoselectivity to be modulated to favor either <i>endo-</i> or <i>exo-</i>ester adducts. For cyclopentadiene, the <i>endo</i>-ester adducts were favored regardless of steric perturbation, although catalysis by bulky Lewis acids increased the proportion of <i>exo</i>-ester adducts in some cases. These Lewis acids were incompatible with the dihydropyridine diene as they induced its decomposition

Total Synthesis of (+)-Lophirone H and Its Pentamethyl Ether Utilizing an Oxonium–Prins Cyclization

The first total synthesis of (+)-lophirone H (<b>1</b>) and its pentamethyl ether <b>29</b>, featuring an oxonium–Prins cyclization/benzylic cation trapping reaction, is described