Table The substrate scope of the intramolecular hydroarylation reactions was then investigated using the cobalt complex C9 (Table ). Replacing the oxygen atom on the side chain with a tosylamide, methylene, or sulfur atom yielded tetrahydroquinoline 8c, tetralin 8d, and thiochroman 8e. By contrast, the five-membered and seven-membered ring products were not obtained. The corresponding chromanes (8f, 8g) were also obtained from each substrate comprising a MOM and TBS group, respectively. Next, we synthesized more complex molecules. For example, L-tyrosinederived compound 7j afforded 8j without racemization. The effect of an olefin moiety on the reactivity was then investigated and the optimum catalyst was found to depend on alkene substitution. Complex C1 was superior to complex C9 for monosubstituted alkenes 8k. However, for trans-1,2-disubstituted alkenes 8l, the difference was more pronounced, with complex C9 not affording a cyclized product, while complex C1 afforded a cyclized product in excellent yield.