Abstract: | 1-, 2-cis-, 2-trans-, and 3-trans-heptenes (C7)are isomerized either very slowly or not at all with IrX(CO)L2 at 80°C in toluene and under N2. However, under the conditions of hydrogenation fast isomerisation takes place. With IrCl(CO)L2 as catalyst the rate of isomerisation decreases the order: 1-C7 ∼ 2-cis-C7 > 3-trans-C7 > 2-trans-C7. This sequence is independent of the ligand L in lrCl(CO)L2, however, with a particular isomer the rate of isomerisation is a function of L in the order L = PPh3 > P(C6H11)3 > P(OPh)3. |