Why Sparteine?
I always scratch my head when papers like this one show up in the ASAPs. Sparteine is a weird chiral ligand. The (+) version is comparatively inexpensive ($18/gram right now at Oakwood if you buy 10 grams), but the (-) version is infamously expensive or impossible to source ($595/gram right now at Oakwood). The paper in question only mentions the (+) version, so if you want the other enantiomer, you'll need to shell out some cash or find another ligand system. I can't help but think there had to be a more flexible chiral amine scaffold to go after.