Phosphorus NMR characterisation of P-N bond rotamers of a α-P 4 S 3 amide with a conformationally constrained chiral substituent

Academic Article

Abstract

  • Reactions of bicyclic α-P 4 S 3 I 2 with Hpthiq gave solutions containing α-P 4 S 3 (pthiq)I and α-P 4 S 3 (pthiq) 2 , where Hpthiq is the conformationally constrained chiral secondary amine 1-phenyl-1,2,3,4- tetrahydroisoquinoline. The expected diastereomers have been characterised by complete analysis of their 31 P{ 1 H} NMR spectra. Hindered P-N bond rotation in the amide iodide α-P 4 S 3 (pthiq)I caused greater broadening of peaks in the room-temperature spectrum of one diastereomer than in that of the other. At 183 K, spectra of two P-N bond rotamers for each diastereomer were observed and analysed. The minor rotamers showed strong evidence for steric crowding, having large diastereomeric differences in 1 J(P-P) and 2 J(P-S-P) couplings (49 Hz, 16% of value, and 4.4 Hz, 19 % of value, respectively). © 2006 WILEY-VCH Verlag GmbH & Co. KGaA.
  • Authors

    Digital Object Identifier (doi)

    Author List

  • Tattershall BW; Knight JG; Andrews MJ; Booth CL
  • Start Page

  • 425
  • End Page

  • 432
  • Volume

  • 632
  • Issue

  • 3