Synthesis and Wittig rearrangement of 3- and 4-benzyloxyphenylphosphonamidates

Funding: We thank EPSRC(UK) and CRITICAT Centre for Doctoral Training for a studentship to R.A.I. (Grant EP/L016419/1).A series of seven O-ethyl-N-butylphenylphosphonamidates with benzyl ether substituents at the para or meta position have been prepared and fully characterised. Upon treatment with n-butyllithium in THF at RT, these undergo Wittig rearrangement in six cases to give the novel phosphonamidate-substituted diarylmethanols in moderate to good yield.Publisher PDFPeer reviewe

Access to diarylmethanols by Wittig rearrangement of ortho-, meta- and para-benzyloxy-N-butylbenzamides

Authors thank EPSRC (UK) for a DTA studentship to ADH (Grant EP/L505079/1), EPSRC (UK) and CRITICAT Centre for Doctoral Training for a studentship to RAI (Grant code: EP/L016419/1) and the EPSRC UK National Mass Spectrometry Facility at Swansea University.The N-butyl amide group, CONHBu, has been found to be an effective promoter of the [1,2]-Wittig rearrangement of aryl benzyl ethers and thus allow the two-step synthesis of isomerically-pure substituted diarylmethanols starting from simple hydroxybenzoic acid derivatives. The method is compatible with a wide range of functional groups including methyl, methoxy and fluoro, although not with nitro and, unexpectedly, is applicable to meta as well as ortho and para isomeric series.Publisher PDFPeer reviewe

Oxazoles

Developments in the chemistry of five-membered ring heterocycles containing non-adjacent oxygen and nitrogen atoms in the period 2007–2020 are reviewed. Application of theoretical and structural methods to these compounds is described including X-ray structure determination. The reactions and ring synthesis of oxazoles, oxazolines, oxazolidines and oxazolidinones are discussed in detail with the synthetic routes categorised according to the source of the ring atoms. Applications are dominated by the development of new chiral oxazoline ligands for metal-promoted asymmetric reactions and an extensive listing of these is provided together with several other important applications in the medicinal, polymer and photophysics areas