Fig. 2. Evaluation of conditions for cobalt-catalyzed double hydroboration of 1,5-diene 1a.
Reaction conditions: 1a (0.200 mmol), HBpin (0.500 mmol), Co(acac)2 (4.0 μmol), ligand (4.0 μmol), heptane (0.5 mL), 4 h, yield was determined by GC (gas chromatography) analysis using tridecane as internal standard and yield in parentheses was isolated yield of 2a. #rr is regioisomeric ratio and represents the ratio of the desired gem-bis(boryl)alkane product to the sum of all other bis(boryl)alkane isomers as determined by gas chromatography analysis.*3 mol % cobalt catalyst.