Reaction of 1,1′‐Divinyl Ferrocene with One‐Electron Oxidants: Entry into Functionalised [4]Ferrocenophanes and Observation of an Isotope‐Dependent Chemoselectivity Effect |
| |
| Authors: | Renate M. Gleixner Kévin M. Joly Dr. MaryJane Tremayne Dr. Benson M. Kariuki Dr. Louise Male Dr. Diane M. Coe Dr. Liam R. Cox Dr. |
| |
| Affiliation: | 1. School of Chemistry, University of Birmingham, Edgbaston, Birmingham, B15 2TT (UK), Fax: (+44)?121‐414‐4403;2. Current address: School of Chemistry, Cardiff University, Park Place, Cardiff, CF10 3AT (UK);3. GlaxoSmithKline, Medicines Research Centre, Gunnels Wood Road, Stevenage, Herts. SG1 2NY (UK) |
| |
| Abstract: | 1,1′‐Divinyl ferrocene ( 2 ) reacts with K3[Fe(CN)6] under basic biphasic conditions to give a [4]ferrocenophane ( 4 ) in good yield. Incorporating deuterium labels into the internal positions of the vinyl groups of 2 affects the chemoselectivity of the reaction; thus under identical reaction conditions, [D2]‐ 2 reacts to provide a diol‐functionalised [4]ferrocenophane, [D2]‐D /L ‐ 6 in addition to the expected keto‐alcohol, [D1]‐ 4 . Variants on this one‐electron oxidative cyclisation methodology can be used to give other [4]ferrocenophanes; thus, the reaction of 2 with CuCl2 in MeOH or iPrOH leads to dialkoxy [4]ferrocenophanes 19 and 20 , respectively, whereas the reaction of 2 with benzyl carbamate in the presence of tBuOCl gives a bis(carbamate)[4]ferrocenophane, 21 . Mechanisms to account for the formation of the products, the stereoselectivity, and the unusual isotope‐dependent chemoselectivity in the reaction of 2 and [D2]‐ 2 with K3[Fe(CN)6] are proposed. |
| |
| Keywords: | cyclization cyclophanes isotope effects metallocenes |
|
|
