Gold-Catalyzed Cyclopenta- and Cyclo-heptannulation

Significance

The authors report a gold-promoted reaction cascade leading to five- and seven-membered carbocycles with defined relative ­stereochemistry. Propargyl acetates undergo ­reactions with alkenes to yield cyclopropanation products, which further rearrange through a ring expansion-cyclization reaction. This chemistry is analogous to rhodium-promoted cyclopropanation-cyclo­addition cascades, and is convenient for obviating the use of diazo compounds.