We assumed the N-H functionality might be detrimental to C=C transposition and synthesized the N-H methylated complexes Mn-6 and Mn-7 based on Mn-4 and Mn-5 (See Supporting Information for synthetic details). Interestingly, once N-H functionality is blocked, Mn complexes start exhibiting the transposition activity (entries 4, 5) with Mn-7 giving the highest yield in the model reaction (61%). The yield and E-selectivity in product 2a could be increased to 89% and 91:9 (E:Z) in a prolonged run (entry 6). Further screening of solvents and reaction temperatures confirmed the THF solvent and 60 °C temperature to be optimal for the catalytic performance of Mn-7 (see Table ). Control experiments indicated the necessity of the catalyst activation with KBHEt 3 that typically allows for more selective generation of Mn hydrides (entries 7, 8). a Reaction conditions: substrate 1 (0.25 mmol), Mn-7 (1 mol%), and 2 mol% KBHEt 3 in 0.5 mL of THF at 60 °C for 24 h. b 5 mol% Mn-7 was used instead. Reaction was performed with 4 mol% Mn-7 at 70 °C in toluene instead.