## 3 Results and Discussion
Furthermore, provided that the metal possesses adequate surface area, the reaction rate can be controlled by adjusting the amount of nitrogen ligand, which determines the concentration of the formed catalytic complex. As a result, in the SARA process, some species required in the ARGET process (such as CuCl\({}_{2}\) and ascorbic acid) can be replaced by a piece of copper wire. A small amount of carbonate (~5 mol%) was also maintained [29], due to the ability of the EtOH/Na\({}_{2}\)CO\({}_{3}\) couple to function as a reducing agent [30]. The SARA ATRC was successfully applied to **1**, resulting in a clean and complete conversion into the expected dichloro-\(\gamma\)-lactam **2** within 16 h at 37 \({}^{\circ}\)C (entry 1, Table 1). Subsequently, one mole of bromide salt for each mole of substrate was added to achieve partial AERC. A marked effect of the metal cation used, whether lithium (entry 2), sodium (entry 3), or potassium (entry 4), on the formation of different proportions of bromolactam **3** and dichlorolactam **2** was observed. Specifically, sodium bromide/carbonate (entry 3) exhibited the best selectivity towards **3**, while the potassium salts demonstrated a propensity towards **2**. Using the sodium salts as the reference, various solvent polarities (i.e., diverse EtOAc/ EtOH ratios) were explored. Lower polarities (entry 5) worsened the selectivity towards **3**, while a slight improvement was observed when EtOH was increased to 50 vol% (entry 6) or higher (entry 7). Several other interventions aimed at improving the selectivity were investigated, including the following: (i) increasing the amount of bromide (1.5 moles NaBr/ moles of **1**), (ii) adding an anion transporter (5 mol% of Bu\({}_{4}\)N\({}^{+}\)Br\({}^{-}\)/Et\({}_{4}\)N\({}^{+}\)Br\({}^{-}\)), and (iii) adding of a cation-catching species (5 mol% of 15-crown-5 ether). Unfortunately, none of these interventions yielded improved results compared to those obtained in entry 6. The greater selectivity observed at higher EtOH concentrations suggested that salt solubility might play a significant role in determining the reaction's outcome. Accordingly, the addition of a minor amount of a polar co-solvent was evaluated, as shown in Table 2. The addition of some MeCN (entry 1) resulted in a significant improvement in selectivity towards **3**, but also in a reduced reaction rate, highlighted by incomplete conversion. In contrast, DMSO (entries 2, 3, 4) [28] brought to high selectivities towards **3**, along with quantitative conversions of **1**. It is worth noting that the best result was attained including the lowest amount of DMSO (entry 2). \begin{table}
\begin{tabular}{c c c c c c c} \hline \multirow{2}{*}{**Entry**} & **EtOAc** & **EtOH** & \multirow{2}{*}{**Bromide**} & \multirow{2}{*}{**Carbonate**} & \multirow{2}{*}{**Yield of 2 (\%)**} & \multirow{2}{*}{**Yield of 3 (\%)**} \\  & **(mL)** & **(mL)** & & & & \\ \hline
1 & 1.5 & 0.5 & - & Na\({}_{2}\)CO\({}_{3}\) & 100 & - \\
2 & 1.5 & 0.5 & LiBr & Li\({}_{2}\)CO\({}_{3}\) & 30 & 57 \\
3 & 1.5 & 0.5 & NaBr & Na\({}_{2}\)CO\({}_{3}\) & 13 & 71 \\
4 & 1.5 & 0.5 & KBr & K\({}_{2}\)CO\({}_{3}\) & 54 & 30 \\
5 & 1.7 & 0.3 & NaBr & Na\({}_{2}\)CO\({}_{3}\) & 35 & 32 \\
6 & 1.0 & 1.0 & NaBr & Na\({}_{2}\)CO\({}_{3}\) & 15 & 75 \\
7 & 0.5 & 1.0 & NaBr & Na\({}_{2}\)CO\({}_{3}\) & 15 & 75 \\ \hline \end{tabular} Common conditions: **1** (1.00 mmol), carbonate (0.05 mmol), bromide (1.00 mmol), Cu\({}^{0}\) (wire, 1 mm diam. and 20 mm long), solvent (2.0 mL, see Table 1 for relative proportion), TPMA (0.01 mmol), 16 h, 37 \({}^{\circ}\)C. GC yields are reported.  
\end{table} 
Table 1: SARA ATRC/AERC of **1**. Lastly, the addition of water in small amounts (entries 5 and 6) led to an almost complete conversion of **1** into **3**. Such an addition can be conveniently implemented by using 96 vol% ethanol instead of absolute ethanol. An explanation of the observed effect may involve the more efficient solvation of chloride ions by polar solvents compared to bromide ions.