title: Effect of configuration of 2-vinyldiazocarbonyl compounds on their reactivity: experimental and computational study.
abstract: Non-fluorinated vinyldiazo compounds with trans-configuration irrespective of the nature of 3-R(1)-substituent (R(1) = H, Me, TBSO) even under ambient conditions easily cyclize to produce pyrazoles, while cis-stereoisomers undergo similar ring closure only at elevated temperatures or decompose to produce vinyloxocarbene reaction products. The 3-CF3-substituted analogues with cis- or trans-configuration do not produce pyrazoles at all, but on heating furnish only vinylcarbene derived products. DFT calculations of theoretical energy barriers adequately explain the different experimental reactivity found for stereoisomeric vinyldiazocarbonyl compounds, and a new model for their interconversion through the corresponding pyrazoles has been suggested.
authors.affiliation: St-Petersburg State University, Department of Organic Chemistry, University pr. 26, 198504, Saint-Petersburg, Russia. vnikola@VN6646.spb.edu.
authors.forename: Murat B
authors.initials: MB
authors.lastname: Supurgibekov
authors.forename: David
authors.initials: D
authors.lastname: Cantillo
authors.forename: C Oliver
authors.initials: CO
authors.lastname: Kappe
authors.forename: G K Surya
authors.initials: GK
authors.lastname: Prakash
authors.forename: Valerij A
authors.initials: VA
authors.lastname: Nikolaev
mesh_terms: D001391:Azo Compounds / Q000737:chemistry*; D015394:Molecular Structure; D011720:Pyrazoles / Q000138:chemical synthesis* / Q000737:chemistry; D011789:Quantum Theory; D014753:Vinyl Compounds / Q000737:chemistry*
chemical_list: D001391:Azo Compounds; D011720:Pyrazoles; D014753:Vinyl Compounds