title: Component mobility by a minute quantity of the appropriate solvent as a principal motif in the acceleration of solid-supported reactions.
abstract: The effects solvents have on fluoride-promoted heterogeneous hydrolysis and alcoholysis of various organo-phosphorus (OP) compounds on the surface of KF/Al2O3 are described. Solid-state magic angle spinning NMR analyses and SEM microscopy have shown that not only is the identity of the solvent important in these reactions but also its quantity. That is, minimal solvent amounts are favored and much more effective in such solid-supported reactions (and maybe generally) than those featuring solvent-free or excess solvent (>50 wt %) conditions. The addition of a minute quantity of the correct solvent (3-10 wt %, molar equivalent scale) avoids reagents leaching from the matrix, permits mobility (mass transport) of the reaction components and ensures their very high local concentration in close proximity to the solid-support large porous surface area. Accordingly, significant acceleration of reactions rates by orders of magnitude is obtained. Fascinatingly, even challenging phosphoesters with poor leaving groups, which were found to be very stable in the presence of solvent-free KF/Al2O3 or wetted with excess water, were efficiently hydrolyzed with a minute amount of this solvent.
authors.affiliation: Department of Organic Chemistry, Israel Institute for Biological Research, Ness-Ziona 74100, Israel.
authors.forename: Gil
authors.initials: G
authors.lastname: Fridkin
authors.affiliation: Department of Organic Chemistry, Israel Institute for Biological Research, Ness-Ziona 74100, Israel.
authors.forename: Ishay
authors.initials: I
authors.lastname: Columbus
authors.affiliation: Department of Organic Chemistry, Israel Institute for Biological Research, Ness-Ziona 74100, Israel.
authors.forename: Sigal
authors.initials: S
authors.lastname: Saphier
authors.affiliation: Department of Organic Chemistry, Israel Institute for Biological Research, Ness-Ziona 74100, Israel.
authors.forename: Lea
authors.initials: L
authors.lastname: Yehezkel
authors.affiliation: Department of Organic Chemistry, Israel Institute for Biological Research, Ness-Ziona 74100, Israel.
authors.forename: Michael
authors.initials: M
authors.lastname: Goldvaser
authors.affiliation: Department of Organic Chemistry, Israel Institute for Biological Research, Ness-Ziona 74100, Israel.
authors.forename: Daniele
authors.initials: D
authors.lastname: Marciano
authors.affiliation: Department of Organic Chemistry, Israel Institute for Biological Research, Ness-Ziona 74100, Israel.
authors.forename: Nissan
authors.initials: N
authors.lastname: Ashkenazi
authors.affiliation: Department of Organic Chemistry, Israel Institute for Biological Research, Ness-Ziona 74100, Israel.
authors.forename: Yossi
authors.initials: Y
authors.lastname: Zafrani
mesh_terms: D005459:Fluorides / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D009943:Organophosphorus Compounds / Q000737:chemistry*; D060327:Solid-Phase Synthesis Techniques; D012997:Solvents / Q000737:chemistry*; D014867:Water / Q000737:chemistry*
chemical_list: D009943:Organophosphorus Compounds; D012997:Solvents; D014867:Water; D005459:Fluorides