Novel Organophosphorus Oligomers. Synthesis and conformation of ¿-hydroxy phenylphosphinates.

Chapter one reviews the recent progress in the synthesis of phosphonopeptides, pseudopeptides containing a phosphinic, phosphonic or phosphonamide linkage in place of an amide (peptide) linkage. It describes some of the general methods for the synthesis of these pseudopeptides; for example through couplings to the nitrogen of an ¿-aminophosphonic acid, or Michael addition to acrylates, as well as other methods, the scope for which are not as wide yet. It also provides a summary of the reported biological activities of this class of pseudopeptides. Chapter two contains the results and discussion for a novel method for the synthesis of ¿-hydroxy phenylphosphinate oligomers as well as hybrid oligomers containing ¿-hydroxy phenylphosphinic acid and ¿-amino carboxylic acids. In particular, synthesis of a series of dimeric ¿-hydroxy phenylphosphinates are reported. The analysis of these dimers by a combination of NMR spectroscopy, X-ray crystallography and computational methods shows intramolecular hydrogen bonding in these molecules depends on the relative configuration of the carbon and phosphorus atoms. However, although the development of the synthetic methods was successful, the separation and isolation of the diastereomers was not always possible, which hindered a more comprehensive analysis of folding patterns in these molecules. Chapter three contains the experimental procedures, preparation and spectroscopic characterisation of all the chemical compounds. Crystal data and details of crystal structures are in the Appendix.EPSR

B–N, B–O, and B–CN Bond Formation via Palladium-Catalyzed Cross-Coupling of B‑Bromo-Carboranes

Carboranes are boron-rich molecules that can be functionalized through metal-catalyzed cross-coupling. Here, for the first time, we report the use of bromo-carboranes in palladium-catalyzed cross-coupling for efficient B–N, B–O, and unprecedented B–CN bond formation. In many cases bromo-carboranes outperform the traditionally utilized iodo-carborane species. This marked difference in reactivity is leveraged to circumvent multistep functionalization by directly coupling small nucleophiles (-OH, -NH₂, and -CN) and multiple functional groups onto the boron-rich clusters

A synthesis of oligomeric small alpha-hydroxy phenylphosphinates and a study of the conformational preferences of the dimers

A general method for the synthesis of a novel class of oligomers, comprising small alpha-hydroxy phenylphosphinic acid building blocks{,} is reported. A series of dimeric small alpha-hydroxy phenylphosphinates are analyzed by a combination of NMR spectroscopy{,} X-ray crystallography and computational methods

Synthesis and folding properties of α-hydroxy phenylphosphinate pseudopeptides

A general method for the synthesis of novel oligomers comprising α-hydroxy and α-amino phenylphosphinic acid building blocks is reported. A series of dimeric α-hydroxy phenylphosphinates is analyzed by a combination of NMR, X-ray crystallography, and computational methods. Copyright © Taylor & Francis Group, LLC