A scalable synthesis of 5,5'-dibromo-2,2'-bipyridine and its stepwise functionalization via Stille couplings.
The synthesis of 5,5'-dibromo-2,2'-bipyridine and 5-bromo-2,2'-bipyridine, useful intermediates for elaboration into more complex ligands through metal-catalyzed coupling reactions, can be efficiently conducted on a multigram scale from inexpensive starting materials. The described procedure is reliably scalable and suitable for the synthesis of tens of grams of 5,5'-dibromo-2,2'-bipyridine. 5-Bromo-2,2'-bipyridine is produced as a minor product. The 5,5'-disubstituted-2,2'-bipyridine motif has excellent coordination properties and is a versatile building block for the synthesis of functional materials (including biodiagnostics, photovoltaics and organic light-emitting diodes) and complex molecular topologies (including catenanes and trefoil and pentafoil knots). The selective stepwise functionalization of 5,5'-dibromo-2,2'-bipyridine by consecutive Stille couplings is therefore illustrated and documented in detail. The synthesis of 5,5'-dibromo-2,2'-bipyridine takes 4-5 d: 1 d to prepare the key intermediate 2,2'-bipyridine dihydrobromide, 3 d for its reaction with bromine in a steel bomb reaction vessel and 8 h to isolate and purify the final product.
School of Chemistry, The University of Edinburgh, Edinburgh, UK.
Daniel M
DM
D'Souza
David A
DA
Leigh
Marcus
M
Papmeyer
Steffen L
SL
Woltering
D015082:2,2'-Dipyridyl / Q000031:analogs & derivatives* / Q000138:chemical synthesis / Q000737:chemistry*; D006842:Hydrocarbons, Brominated / Q000138:chemical synthesis* / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy
C578993:5,5'-dibromo-2,2'-bipyridine; D006842:Hydrocarbons, Brominated; D015082:2,2'-Dipyridyl