Fig. 4: Substrate Scope of Sequential Hydrosilylation/Hydrohydrazidation of Terminal Alkynes via Ligand Relay Catalysis.

^aReaction conditions: 1 (0.3 mmol), 2 (1.0 equiv.), 3 (1.0 equiv.), Xantphos•CoBr₂ (1 mol %), NaBHEt₃ (3 mol %), L5 (2 mol %), PhSiH₃ (1.2 equiv.), and H₂O (3.0 equiv.) in Et₂O (1.2 mL) under nitrogen at room temperature for 12 h, isolated yield of 4 with complete regioselectivity without additional indications. ^bStirred in THF, without H₂O. ^cStirred for 24 h. ^dL11 (see Supplementary Information) was instead of L5, PhMeSiH₂ was instead of PhSiH₃, without H₂O and stirred for 24 h (7/1 rr). ^eDPEphos•CoBr₂ was instead of Xantphos•CoBr₂, PhSiH₃ was instead of Ph₂SiH₂.