C(sp)–H, S–H, and Sn–H Bond Activation with a Cobalt(I) Pincer Complex

This study focuses on the stoichiometric reactions of 2, 6- (iPr2PO) 2C6H3Co (PMe3) 2 with terminal alkynes, thiols, and tin hydrides as part of an effort to develop catalytic, two-electron processes with cobalt. This specific Co (I) pincer complex proves to be effective for cleaving the C (sp) –H, S–H, and Sn–H bonds to give oxidative addition products with the general formula 2, 6- (iPr2PO) 2C6H3CoHX (PMe3) (X = alkynyl, thiolate, and stannyl groups) along with the free PMe3. These reactions typically reach completion when the substituents on acetylene, sulfur, and tin are electron-withdrawing groups (e. g. , phenyl, pyridyl, and alkenyl groups). In contrast, alkyl-substituted acetylenes, 1-pentanethiol, and tributyltin hydride are partially converted due to the equilibria with the corresponding oxidative addition products. The Co (I) pincer complex is not a hydrothiolation catalyst but capable of catalyzing the hydrostannation of terminal alkynes with Ph3SnH to produce β- (Z) -alkenylstannanes selectively.