Modular Enantioselective Synthesis of 8‑Aza-prostaglandin E₁

We report herein for the first time the enantioselective synthesis of 8-aza-PGE₁. The synthesis used the cross olefin metathesis reaction to connect the 5-vinyl-γ-lactam subunit, prepared from (<i>R</i>)-malic acid via the Ley’s sulfone-based α-amidalkylation protocol (dr = 6.8:1), with the chiral pre-ω-chain. The latter was synthesized in high enantioselectivity from (<i>E</i>)-2-octenol by the Sharpless asymmetric epoxidation and the titanocene-mediated epoxide opening. This modular approach is quite concise and flexible, and requires only eight steps from commercially available reagents

Total Synthesis of (−)-Sessilifoliamide J

An efficient synthesis of the <i>Stemona</i> alkaloid (−)-sessilifoliamide J (<b>1</b>) in 12 steps and 7.7% overall yield from the known building block <b>8</b> is presented. The synthesis features the Corey lactonization reaction and a highly diastereoselective α-methylation reaction to build the spiro-lactone moiety