a) The pH2 protons are added to fumarate (FUM) via a rhodium-based catalyst at 90°C and 20 bar, forming succinate (SUC). The values of the J-couplings read J12 = 7.41 Hz, J13 = −7.15 Hz, and J23 = 5.82 Hz. The SOT sequences ADAPT19 (b) and ECHO23,46 (c) were used to transfer the 1H para order to 13C polarization and consist of RF pulses and free evolution times tAD,α and tE. Note that ADAPT requires heteronuclear decoupling during hydrogenation to preserve singlet state (red bars), whereas ECHO does not. The black bar denotes a 180° spin echo pulse along the x- or y-axis at tE/2.