Table 1.

Screening of conditions for the preparation of 1,1-diborylalkanes from alkenes

Entrya	Ni cat.	Ligand	Base	Solvent	Yield (%)b
1	Ni(COD)2	PCy3	LiOMe	PhMe	39
2	Ni(COD)2	PCy3	LiOBut	PhMe	<5
3	Ni(COD)2	PCy3	Cs2CO3	PhMe	22
4	Ni(COD)2	PCy3	NaOBut	PhMe	Trace
5	Ni(COD)2	PCy3	KOBut	PhMe	<5
6	Ni(COD)2	PCpent3	LiOMe	PhMe	Trace
7	Ni(COD)2	PCyPh2	LiOMe	PhMe	Trace
8	Ni(COD)2	IMes.HCl	LiOMe	PhMe	trace
9	Ni(COD)2	Cy-XantPhos	LiOMe	PhMe	62
10	Ni(COD)2	Cy-XantPhos	LiOMe	THF	52
11c	Ni(COD)2	Cy-XantPhos	LiOMe/NEt3	PhMe/THF	78
12	–	Cy-XantPhos	LiOMe/NEt3	PhMe/THF	0
13	Ni(PPh3)4	PCy3	LiOMe	PhMe	0
14	NiCl2(PCy3)2	PCy3	LiOMe	PhMe	12

Standard reaction conditions: 5% Ni(COD)₂, 5% Cy-XantPhos, 2.0 equiv. B₂pin₂, 1.0 equiv. LiOMe, 0.5 equiv. NEt₃, 0.55 mL PhMe/THF(v:v/10:1) with Ar protection at 130 °C for 1 h

^aFor entry 1–10 and 13–14, 10% Ni(COD)₂ and 20% Ligand, at 130 °C for 12 h

^bGC yield average of two runs using n-tetracosane as internal standard

^cStandard reaction conditions