Unexpected Reaction of (trindane)Mn(CO)3+BF4- with Potassium tert-Butoxide: Three C−H Insertions and a Haptotropic Shift

(η 6 -trindane)Mn(CO) 3 + BF 4 - ( 1 ) reacts with Bu t OK in THF in the presence of alkyl halides (CH 3 I, CH 2 CHCH 2 Br, CH 2 Cl 2 ) to yield the corresponding (η 6 -C 15 H 18 )Mn(CO) 2 X, where X = I, Br, Cl. In contrast, 1 and Bu t OK react, in the presence of a donor ligand, to generate (η 5 -C 15 H 15 )Mn(CO) 2 L, where L = CO, P(OMe) 3, PPh 3, in which the metal has migrated from the central ring onto a peripheral ring that has lost three hydrogens; (η 6 -indane)Mn(CO) 3 + BF 4 - behaves similarly. A mechanism is proposed in which the initially formed (η 6 -trindane)Mn(CO) 2 CO 2 Bu t suffers loss of CO 2 and isobutene to yield the hydride (η 6 -trindane)Mn(CO) 2 H, which in turn undergoes three successive C−H insertions with concomitant loss of 2 mol of dihydrogen.