Figures (9)  Tables (4)

    • Figure 1. 

      The possible reactive channels of the I32CA reaction.

    • Figure 2. 

      The synthesis of tetracyclic isoxazolidines from a simple oxindole.

    • Figure 3. 

      Reactive pathways associated with the I32CA of 1.

    • Figure 4. 

      Curves of energy profiles in toluene solvent of the I32CA reactive paths of (E)-N-((2-((methylbut-2-en-1-yl)thio)-1H-indol-3-yl)methylene)methanamine oxide 1.

    • Figure 5. 

      TSs optimised structures of the I32CA of (E)-N-((2-((methylbut-2-en-1-yl)thio)-1H-indol-3-yl)methylene)methanamine oxide 1, showing the lengths (in Å, in red), and BO (in blue) of bonds under formation.

    • Figure 6. 

      Structure of different selected points together with the position of the ELF valence basin attractors of the chosen structures corresponding to the fused-endo pathways of the I32CA of 1.

    • Figure 7. 

      NCI analysis of TS2n and TS2x structures with isosurfaces = 0.40.

    • Figure 8. 

      Plots of RDG for TS2n and TS2x structures.

    • Figure 9. 

      QTAIM molecular schematisation of TS2n and TS2x together with bond paths and (3,−1) critical points.

    • System ΔEGas phase (kcal/mol) ΔEToluene (kcal/mol)
      TS2n 18.7 21.8
      TS2x 34.9 37.0
      TS3n 30.5 31.8
      CA2n −17.5 −15.3
      CA2x −13.3 −12.1
      CA3n −9.1 −7.7

      Table 1. 

      Values of relative energies of (E)-N-((2-((-methylbut-2-en-1-yl)thio)-1H-indol-3-yl)methylene)methanamine oxide 1, TSs, and CAs in gas-phase and solution of toluene.

    • System ΔH (kcal/mol) ΔS (cal/mol/K) ΔG (kcal/mol)
      TS2n 20.8 −22.2 28.6
      TS2x 35.7 −20.3 42.8
      TS3n 30.8 −23.3 38.9
      CA2n −14.5 −26.6 −5.2
      CA2x −11.3 −24.8 −2.6
      CA3n −7.1 −27.4 2.5

      Table 2. 

      Relative thermodynamic function values for the TSs and CAs of the I32CA of (E)-N-((2-((methylbut-2-en-1-yl)thio)-1H-indol-3-yl)methylene)methanamine oxide 1.

    • MC2n TS2n P1 P2 P3 P4 P5 CA2n
      d(C3−C4) 2.91 1.97 1.77 1.66 1.57 1.54 1.48 1.47
      d(O1−C5) 3.01 2.23 2.00 1.87 1.75 1.71 1.62 1.58
      V(O1−N2) 1.31 1.10 1.00 0.95 0.91 0.88 0.88 0.86
      V(N2−C3) 3.98 2.49 2.13 1.95 1.88 1.84 1.83 1.83
      V(C4−C5) 1.81, 1.75 2.86 2.28 2.13 2.06 2.01 2.00 1.99
      V(C3…C4) − − − 1.64 1.74 1.81 1.84 1.86
      V(O1…C5) − − 0.30 0.78 0.98 1.09 1.15 1.16
      V(C3) − 0.43 0.63 − − − − −
      V(C4) − 0.55 0.82 − − − − −
      V(O1) − − − − − − − −
      V(C5) − − − − − − − −

      Table 3. 

      Electron density of the pertinent basins of the chosen points on the reactive fused-endo pathways of the I32CA of 1.

    • Interaction ρcbcp $\nabla $2ρbcp Hbcp
      TS2n O1…C5 0.79 0.12 -0.15
      C3…C4 0.58 0.43 0.13
      H…H 0.44 0.16 0.99
      H…S 0.99 0.32 0.15
      TS2x O1…C5 0.69 0.18 -0.97
      C3…C4 0.65 0.33 -0.16
      H…H 0.30 0.81 0.30

      Table 4. 

      QTAIM parameters associated with the (3,−1) cps associated with TS2n and TS2x.