Gold-Catalyzed Sequential Cyclization of 1-En-3,9-Diyne Esters to Partially Hydrogenated 3H-Dicyclopenta[a,b]naphthalenes

• Published in: Chemistry : a European journal Vol. 22; no. 19; pp. 6532 - 6536
• Main Authors: Rao, Weidong, Boyle, Joshua William, Chan, Philip Wai Hong
• Format: Journal Article
• Language: English
• Published: Germany Blackwell Publishing Ltd 04-05-2016; Wiley Subscription Services, Inc
• Subjects: Carbenes; carbocycles; Chemistry; Construction; Cycloaddition; cycloisomerization; Esters; Gold; homogeneous catalysis; Isomerization; Migration; Pathways; Robustness; Strategy; synthetic methods; gold; carbocycles; homogeneous catalysis; cycloisomerization; synthetic methods
• ISSN: 0947-6539; 1521-3765
• DOI: 10.1002/chem.201600915

A synthetic method that relies on a gold(I)‐catalyzed cycloisomerization of 1‐en‐3,9‐diyne esters to spiro[4.4]non‐2‐ene‐substituted 1,2‐dihydronaphthalenes is described. Robust with a wide variety of substitution patterns tolerated, the reaction provides the first example of a one‐step strategy to construct such novel and architecturally challenging members of the carbocycle family in good to excellent yields. A mechanism is proposed in which the sequential cycloisomerization pathway was thought to involve a gold‐catalyzed 1,3‐acyloxy migration/Nazarov cyclization followed by a formal [4+2] cycloaddition to give the tetracarbocyclic product.
A NHC–gold(I)‐catalyzed sequential cycloisomerization of 1‐en‐3,9‐diyne esters to partially hydrogenated 3H‐dicyclopenta[a,b]naphthalenes, which are novel and architecturally challenging members of the carbocycle family of compounds, is described (see scheme; NHC=N‐heterocyclic carbene).