NEW SYNTHESES OF CP-ASTERISK-TH-2(PH)(2) AND CP-ASTERISK-TH-2(ME)(ARYL) DERIVATIVES

Citation
Af. England et al., NEW SYNTHESES OF CP-ASTERISK-TH-2(PH)(2) AND CP-ASTERISK-TH-2(ME)(ARYL) DERIVATIVES, Organometallics, 13(9), 1994, pp. 3491-3495
Citations number
45
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Chemistry Inorganic & Nuclear","Chemistry Inorganic & Nuclear
Journal title
ISSN journal
0276-7333
Volume
13
Issue
9
Year of publication
1994
Pages
3491 - 3495
Database
ISI
SICI code
0276-7333(1994)13:9<3491:NSOCAC>2.0.ZU;2-5
Abstract
The complex Cp(2)ThPh(2) (1) is known to be a useful precursor in eli mination reactions to yield transient benzyne adduct. This complex may be prepared in improved yield from the reaction of PhMgBr with Cp2Th Cl2 in the presence of p-dioxane. Ortho-substituted precursors CpTh-2 (Me)(o-MeOC(6)H(4)) (2), CpTh-2(Me)(o-MeC(6)H(4)) (3), and Cp*Th-2(Me )(2,5Me(2)C(6)H(3)) (4) are reported for the first time, having been p repared in one-pot procedures using a similar method. The respective i ntermediate monohalide complexes have also been prepared at room tempe rature. The tolyl and xylyl derivatives exist as pairs of rotamers in solution, demonstrating the significant steric constraints imposed on this type of complex by ortho substituents. Halide exchange is observe d in the preparation of the aryl-halide complexes when arylmagnesium b romides are employed. The extent Of this exchange is influenced by the addition of p-dioxane to reaction mixtures.