A new Chemical Science study from ICIQ researchers shows why some gold(I)-catalysed alkoxycyclisations produce products with very different enantiomeric ratios, even when formed in the same reaction. The work is a collaboration between the group of Prof. Antonio M. Echavarren (experimental) and the group of Prof. Feliu Maseras (computational).
The team reports the first enantioselective cyclisations of bromo‑1,5‑ and bromo‑1,6‑enynes, including spiro compounds. During the study, they observed that a key step of the reaction can be reversible. When this happens, part of the reaction mixture can racemise, explaining why an alkoxycyclisation product is enantioenriched while the cycloisomerisation product is almost racemic.
The selectivity also depends on the amount of methanol present: low quantities make the hydride shift competitive, while higher amounts speed up the alkoxycyclisation and lead to enantioenriched products.
These results help explain the mechanisms behind one of the most representative transformations in gold(I) catalysis and “shed new light on the complex mechanisms of gold(I)-catalyzed alkoxycyclizations.”
The study also highlights the importance of highly polarised haloalkynes, versatile molecules whose dual reactivity allows further functionalisation and efficient construction of complex structures.
Main co-authors Dr. Andrea Cataffo and Dr. Eduardo García‑Padilla describe the project as a long experimental–computational effort triggered by an unexpected observation: two products formed in the same reaction showed very different enantiomeric outcomes. Their investigation reveals the mechanistic reason behind this behaviour and points to overlooked complexity in apparently simple catalytic cycles.
Reference publication
Enantioselective Cyclization of Bromoenynes: Mechanistic Understanding of Gold(I)-Catalyzed Alkoxycyclizations
Cataffo, A.; García-Padilla, E.; Escofet, I.; Fincias, N.; Arnanz, A.; Zuccarello, G.; Tian, G.; Cai, L.; Khorasani, F.; Maseras, F.; Echavarren, A. M.
Chem. Sci. 2026
DOI: 10.1039/D5SC09023G
La entrada ICIQ researchers clarify unexpected behaviour in gold‑catalysed reactions se publicó primero en ICIQ.
