NMR Data for "Unveiling a Key Catalytic Pocket for the Ruthenium NHC-Catalysed Asymmetric Heteroarene Hydrogenation" (DOI: 10.1039/D1SC06409F)

# NMR Data for "Unveiling a Key Catalytic Pocket for the Ruthenium NHC-Catalysed Asymmetric Heteroarene Hydrogenation" (DOI: 10.1039/D1SC06409F)

In the following, the original NMR Data for the publication "Unveiling a Key Catalytic Pocket for the Ruthenium NHC-Catalysed Asymmetric Heteroarene Hydrogenation" (DOI: 10.1039/D1SC06409F) is provided. 

## Experimental methodology and associated data

### Dataset 200113.40a

Inside an argon filled glovebox, 4.6 mg of **1-A** (5.4 µmol) was dissolved in 0.65 mL THF-d8 (distilled over sodium/benzophenone and stored over 3 Å molecular sieves), yielding a clear, dark yellow solution. The solution was then transferred into a medium pressure J Young NMR tube and sealed. Subsequently, initial NMR spectra under argon atmosphere were recorded (t = 0 h).

Afterwards, 2 bar of H2 pressure were applied to the J Young NMR tube, resulting in a partial H2 pressure of 1 bar (due to the presence of 1 bar argon). After shaking to dissolve the added H2, a slow color change to orange could be observed. The reaction was monitored using 1H NMR (Bruker AV 400, 400 MHz), showing consumption of dissolved H2 as evidenced by a decrease in intensity for the H2 signal at δ(1H) = 4.55 ppm. Six hours after the first addition of H2, the J Young NMR tube was re-pressurized with 2 bar H2, and again after 36 h, shaking the NMR tube regularly to dissolve H2. After the third pressurization, no further decrease of dissolved H2 could be observed.

#### NMR experiments and timestamps

File name | NMR Experiment | Time stamp / h (relative to H2 addition)
--- | --- | ---
200113.40a.1 | 1H | 0
200113.40a.2 | 1H | 0
200113.40a.3 | 1H | 0.5
200113.40a.4 | 1H | 1
200113.40a.5 | 1H | 2.5
200113.40a.6 | 1H | 2.5
200113.40a.7 | 1H | 5 
200113.40a.8 | 1H COSY-45 | 5
200113.40a.9 | 1H | 6.5
200113.40a.10 | 1H | 22.5
200113.40a.11 | 1H | 30
200113.40a.12 | 1H | 31
200113.40a.13 | 29Si-inept | 31
200113.40a.14 | 1H-29Si HMBC | 31
200113.40a.15 | 1H | 45.5
200113.40a.16 | 1H-29Si HMBC | 45.5
200113.40a.17 | 1H | 55
200113.40a.18 | 1H | 69.5
200113.40a.110 | 1H (larger measurement window) | 22.5
200113.40a.111 | 1H (larger measurement window) | 30
200113.40a.115 | 1H (larger measurement window) | 45.5
200113.40a.117 | 1H (larger measurement window) | 55
200113.40a.118 | 1H (larger measurement window) | 69.5

### Dataset 200117.40a

69.5 h after the first addition of H2 no significant changes could be observed in the 1H NMR spectra anymore. At this point, 0.15 mL of a 0.052 M solution of benzofuran in THF-d8 (7.8 µmol benzofuran, ca. 1.5 equivalents relative to **1-A**) were added to the NMR tube while applying 2 bar of H2 pressure. No significant color change was observed upon addition of the substrate. Subsequently, the NMR tube was sealed and the reaction was monitored using 1H NMR for an additional 119 h, especially following the hydride signals at δ(1H) = −3.7 ppm and δ(1H) = −3.8 ppm as well as the signals of 2,3-dihydrobenzofuran at δ(1H) = 4.48 ppm and δ(1H) = 3.15 ppm. After 119 h of reaction time, the color of the reaction solution had changed to light orange.

#### NMR experiments and timestamps

File name | NMR Experiment | Time stamp / h (relative to substrate addition)
--- | --- | ---
200117.40a.1 | 1H | 0.5
200117.40a.2 | 1H | 1.5
200117.40a.3 | 1H | 7
200117.40a.4 | 1H | 24
200117.40a.5 | 1H | 24.5 
200117.40a.6 | 1H | 72 
200117.40a.7 | 1H COSY-45 | 72
200117.40a.101 | 1H (larger measurement window) | 0.5
200117.40a.103 | 1H (larger measurement window) | 7
200117.40a.104 | 1H (larger measurement window) | 24