Figure 3 - Example procedures of partial reduction methodology.

From the following article

The partial reduction of electron-deficient pyrroles: procedures describing both Birch (Li/NH₃) and ammonia-free (Li/DBB) conditions

Timothy J Donohoe & Rhian E Thomas

Nature Protocols 2, 1888 - 1895 (2007) Published online: 2 August 2007

doi:10.1038/nprot.2007.245