1372464-76-0Relevant academic research and scientific papers
Conformational preferences of oxy-substituents in butenolide- tetrahydropyran spiroacetals and butenolide-piperidine spiro-N,O-acetals
Naud, Sebastien,MacNaughton, Sarah J.,Dyson, Bryony S.,Woollaston, Daniel J.,Dallimore, Jonathan W. P.,Robertson, Jeremy
, p. 3506 - 3518 (2012/05/21)
We describe the synthesis of a series of oxy-substituted butenolide spiroacetals and spiro-N,O-acetals by oxidative spirocyclisation of 2-[(4-hydroxy or 4-sulfonamido)butyl]furans. The axial-equatorial preference of each oxy-substituent is investigated (NMR) by an acid-catalysed thermodynamic relay of configuration between the spiro- and oxy-centres. The axial site is preferred for most oxy-substituents at synthetically useful levels. The potential origins of this preference are discussed in terms of a stabilising gauche effect combined with the influence of solvation. These results have relevance to the synthesis of bis(acetylenic)enol ether spiroacetals including AL-1 and related compounds.
