Stereoselective Suzuki-Miyaura cross-coupling reactions of potassium alkenyltrifluoroborates with alkenyl bromides.
[reaction: see text] The stereoselective synthesis of conjugated dienes using air-stable potassium alkenyltrifluoroborates as coupling partners is described. The palladium-catalyzed cross-coupling reaction of potassium (E)- and (Z)-alkenyltrifluoroborates with either (E)- or (Z)-alkenyl bromides proceeds readily with moderate to excellent yields to give the corresponding (E,E)-, (E,Z)-, (Z,E)-, or (Z,Z)-conjugated dienes stereospecifically. The cross-coupling can generally be effected using 5 mol % of Pd(OAc)2, 10 mol % of PPh3, and 3 equiv of Cs2CO3 in THF-H2O (10:1). A variety of functional groups are tolerated in both coupling partners.
Molander
Gary A
GA
Roy and Diana Vagelos Laboratories, Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, USA. gmolandr@sas.upenn.edu
Felix
Luciana A
LA
D000475:Alkenes / Q000138:chemical synthesis* / Q000737:chemistry; D001881:Borates / Q000737:chemistry*; D001966:Bromine / Q000737:chemistry*; D002384:Catalysis; D013237:Stereoisomerism
D000475:Alkenes; D001881:Borates; D001966:Bromine