Ruthenium-catalysed coupling of aromatic ketones with alkynylsilanes yielded in most cases ortho vinylation adducts in high yield. The predominant stereochemistry of the newly introduced double bond was E in all but a few cases. In contrast, 1-acetylnaphthalene underwent a one-pot insertion-cyclisation sequence yielding cyclopenta[a]naphthalene derivatives. A bis acetylene gave both mono and bis insertion products. (C) 1999 Elsevier Science S.A. All rights reserved.