title: Effective and highly stereoselective coupling with vinyldiazomethanes to form symmetrical trienes.
abstract: Diazo coupling reactions are capable of forming E,E,E-trienes from cinnamaldehydes in good yield. An efficient methodology is reported for the production of styryldiazomethanes that are subsequently used with catalysis for coupling and for cyclopropanation. A vast difference in product selectivity is seen with styryldiazomethane generated from the corresponding hydrazone via manganese dioxide oxidation and that formed in situ by treatment of the tosylhydrazone sodium salt of cinnamaldehyde with transition metal catalysts. This observation impacts understanding of the reaction mechanism for diazo decomposition.
authors.affiliation: Department of Chemistry, University of Arizona, Tucson 85721, USA. mdoyle@u.arizona.edu
authors.forename: Michael P
authors.initials: MP
authors.lastname: Doyle
authors.forename: Ming
authors.initials: M
authors.lastname: Yan
mesh_terms: D000475:Alkenes / Q000138:chemical synthesis* / Q000737:chemistry*; D001391:Azo Compounds / Q000737:chemistry; D002384:Catalysis; D003500:Cyclization; D006835:Hydrazones / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D008697:Methane / Q000031:analogs & derivatives / Q000737:chemistry*; D015394:Molecular Structure; D011720:Pyrazoles / Q000737:chemistry; D013055:Spectrophotometry, Infrared; D013237:Stereoisomerism; D020058:Styrene / Q000737:chemistry; D013343:Styrenes / Q000737:chemistry; D014753:Vinyl Compounds / Q000737:chemistry*
chemical_list: D000475:Alkenes; D001391:Azo Compounds; D006835:Hydrazones; D011720:Pyrazoles; D013343:Styrenes; D014753:Vinyl Compounds; D020058:Styrene; D008697:Methane