| 摘要 |
Stoichiometric and catalytic chemical transformations may be carried out in solution using novel fluorous multiphase systems (FMS). "Fluorous" denotes a carbon-fluorine bond rich organic molecule derived by replacing hydrogen atoms bonded to carbon atoms with fluorine. The FMS consists of a fluorous phase containing a fluorous solvent, typically a fluorocarbon or a fluorohydrocarbon (with or without substituent groups), and a reagent or a catalyst containing a sufficient number of fluorous moieties to render it preferentially soluble in the fluorous solvent and located at the interface of the fluorous and nonfluorous phases. The nonfluorous (i.e. the second) solvent, may be any known organic or nonorganic solvent(s) with limited or no solubility in the fluorous solvent that is effective for dissolving the reactants and/or separating the reaction products (e.g., a nonfluorous solvent having a Hildebrand solubility parameter of at least about 18.0 MPa<1/2 >). The reaction can occur simultaneously in the fluorous phase and at the interface of the phases. The FMS reagents and FMS catalysts contain sufficient number of fluorous moieties to render them preferentially soluble into the fluorous phase and at the interface without impairing the efficacy or participation of the catalyst or reagent in the reaction which is maintained in a liquid or fluid phase. The preferred fluorous moieties are linear, branched and carbocyclic fluorocarbon alkyl chains with high carbon numbers that enable the catalyst or reagent to remain fluorous-phase compatible. The fluorous moieties may also contain O, S, N, P, As and Si, that assist in rendering the catalysts and reagents fluorous phase compatible. The FMS reagents and catalysts can be prepared by (1) fluorination (i.e., replacement of C-H bonds with fluorine); (2) fluorofunctionalization, e.g., the attachment of fluorous moieties to the reagents or catalysts; or (3) by total synthesis. The fluorous multiphase systems have utility to facilitate the separation of the FMS catalyst or spent FMS reagent, which has utility in the design and synthesis of catalysts and reagents with high product selectivity, resulting in especially environmentally friendly processes. |
