Exploring the Potential of a Non-Phosphine Cobalt System for Alcohol Activation: Expedition of C–C and C–N Bond Formation

"Non-phosphine cobalt complexes have been relatively underexplored in the area of Acceptorless Dehydrogenation and Borrowing Hydrogen" catalysis. Most importantly, cobalt chemistry has not been specifically explored for the C-alkylation of methylene ketones. Herein, we developed NNO and NNN-Co complexes. Further, we have explored the potential of the synthesized complexes for the C-alkylation of challenging methylene ketones. The protocol displays a wide range of functional group tolerance. Important substrates including aliphatic alcohols bearing distal double bonds couple with ketones effectively. Additionally, the protocol demonstrates high efficiency in synthesizing multi-substituted quinolines, and 5,6-dihydrobenzo[c]acridine and is also effective for the C-alkylation of methyl N-heteroarenes. The control experiments eliminate the possibility of a radical pathway and also confirm that the complex functions as a homogeneous catalyst. Deuterium scrambling experiments prove the involvement of Borrowing Hydrogen chemistry in the alkylation process.