Theoretical study on the structural properties of various solvated metalated 3-halo-1-azaallylic anions.
Metalated 3-halo-1-azaallylic anions are important building blocks for the preparation of a wide variety of heterocyclic and highly functionalized compounds. A theoretical description of the structural properties of halogenated 1-azaallylic anions in vacuo and in tetrahydrofuran (THF) solution is presented to gain insight into their reactivity behavior. The configurational flexibility of fluorinated and chlorinated 1-azaallylic anions is examined, and it is shown that these anions have far less configurational flexibility as compared with nonhalogenated analogues, with a strong preference to occur as Z/anti isomers. In addition, the driving force for transmetalation, that is, the replacement of the lithium cations with K(+), Cu(+), ZnCl(+), CuCl(+), or MgBr(+) is studied. To obtain reliable results, the structures were modeled in THF using the combined implicit/explicit solvent approach resulting in different coordination numbers for lithium in the Z/anti and E/anti isomers. Calculations on dimerization energies show that coordination with THF is energetically preferred over aggregation.
Center for Molecular Modeling, Ghent University, Proeftuinstraat 86, B-9000 Ghent, Belgium.
Bart
B
De Sterck
Veronique
V
Van Speybroeck
Sven
S
Mangelinckx
Guido
G
Verniest
Norbert
N
De Kimpe
Michel
M
Waroquier
D001372:Aza Compounds / Q000737:chemistry*; D005663:Furans / Q000737:chemistry; D008670:Metals / Q000737:chemistry*; D008958:Models, Molecular; D008968:Molecular Conformation; D009942:Organometallic Compounds / Q000737:chemistry*; D011789:Quantum Theory; D012997:Solvents / Q000737:chemistry*; D013237:Stereoisomerism
D001372:Aza Compounds; D005663:Furans; D008670:Metals; D009942:Organometallic Compounds; D012997:Solvents; C018674:tetrahydrofuran