Trinity: The combination of rhodium/phosphine/amine⋅HBr enables the highly selective catalytic cross‐cyclodimerization of diarylacetylenes with aliphatic alkynes to afford the corresponding multiply substituted naphthalenes in good‐to‐high yields. The catalyst system also allows the use of some alkenes as the coupling partners, which provides a facile route to highly functionalized dihydronaphthalenes (see scheme).

. -Cross-cyclodimerization as well as homo-dimerization of diarylacetylenes (I) and (V) is smoothly achieved in the presence of a Rh(I)-PPh3--amine·HBr catalytic system. The reaction provides access towards polysubstituted naphthalene derivatives, e.g. (III), (IV) or (VI), in good yields. Cross-cyclodimerization can be carried out with dialkylalkynes (II) as well as olefins (XIII), (XV). Moderate to high regioselectivity is achieved for unsymmetrically substituted alkynes.