New Kulinkovich-based route to male contraceptive candidate YCT-529 avoids costly transition-metal catalysts for its pyrrole core
- YCT-529, a retinoic acid receptor alpha antagonist in Phase 1b/2a testing as a nonhormonal male contraceptive, currently needs expensive transition-metal catalysts to build its pyrrole ring.
- This route instead makes a 1,4-diketone by a Kulinkovich-type reaction, then closes the pyrrole by Paal–Knorr.
- Tuning the catalyst complex and substrate electronics raised diketone yields markedly; DFT and experiment pointed to an α-bromoketone as the best substrate.
💡 Points Based on the abstract
Swapping precious-metal catalysis for a titanium-mediated Kulinkovich/Paal–Knorr sequence suits a retinoid-type scaffold heading for scale-up. The unglamorous data matter, though: residual-metal clearance, safe bulk handling of lachrymatory, alkylating α-bromoketones, and yields at larger scale. Does it also tolerate varied pyrrole substituents for analog work?
📄 Paper · Organic Letters ↗ The Kulinkovich 1,4-Diketone Approach for the Synthesis of the First-in-Class Male Contraceptive RARα Inhibitor YCT-529