Gold(I)-catalyzed macrocyclization of 1,n-enynes.

The gold(I)-catalyzed [2 + 2] cycloaddition of large 1,n-enynes (n = 10–16) provides access to 9- to 15-membered ring macrocycles incorporating a cyclobutene moiety. The reaction requires the use of a gold(I) catalyst bearing a sterically hindered biphenylphosphine ligand.