Change from the standard conditions Yield of 2aa (%) ). Diboron reductants appeared to be important for the radical 1,2-N-shift/C-H coupling sequence, and B2neo2 showed the highest efficiency when compared to the other diboron or metal reductants studied, including B2pin2, B2(OH)4, B2(cat)2, and Zn and Mn powders (entries 9-13). Other solvents, such as DMF, DMA, and NMP, significantly decreased the product yield in this radical relay (entries 14-16). In addition, the replacement of K2CO3 with other bases such as K3PO4 or Na2CO3 did not yield better results (entries 17-18). A significant decrease in the product yield was observed when the reaction temperature was reduced to 50 °C (entry 19). dimethyl acetamide, isolated yield. The diastereomeric ratio (dr) and regioselective ratio (rr) were determined using 1 H NMR analysis. 2.0 equiv of LiBr was added.