13C solution-state

Selected and 13C solution-state (CDC13), and solid-state cp/mas 13C-NMR parameters for the quaternary ammonium salt are listed in Table 10. The termini of the benzo fragment were differentiated by the finding of a 6.8% intensity increase into 8 4.77 H(62) exo upon <5 8.12 H(7). The two A -methyl groups were differentiated by the observance of a 7.1% intensity increment into 8 4.16 H(3) axial upon <5 3.35 NC//3 axial. The lists of solid-state 13C chemical shifts of the two pseudopolymorphs are seen to be different (especially those for C(l)). The C(l)-0(2)-C(3)-C(4) dihedral angle was 135° and 78° in crystalline (reference,IS,3R)-TCC (33) and (retro-inverso,lS,3R)-BC (34), respectively. Thus, also in this case, the cp/mas chemical shifts of 8 84.34 (for 33) and 8 76.87 (for 34) can be easily rationalized in terms of a gamma-gauche effect. 

Racemic (1 / A,3RiS )-3-methyl-1-phenyl-3,4,5,6-tetrahydro-l//-2,5-benzoxazocine-5-carbonitrile (35) crystallized as a racemic compound in an achiral space group.1 X-ray structure analysis showed that one of the enantiomers in the crystal was bent into the (retro,S)-TBC conformation (for torsion angles of the X-ray structure, see Fig. 18).1 TBC is a relatively rare d.v-cyclooctene conformation, and is the fourth and highest energy conformation for d.v-cyclooctene within an energy window of 33.4 kJ from the ground state.1 Selected FI and 13C solution-state and 13C cp/mas... 

---