Abstract The reactions of a number of chromium carbene complexes (CO) 5 Cr C (OMe) R (R= Ph, o-OMePh, p-OMePh, oO-tBuPh, 1-C 6 H 9, 1-C 5 H 7 O) were examined with a variety of acetylenes (R′ CCR 2, R 1, R 2= H, Me, Et, n-Pr, Ph, SiMe 3) in solvents ranging from low to high coordinating ability. The high selectivity for the benzannulated product from the reactions of simple α, β-unsaturated complexes is not affected by changes in solvent ...