“…Controle xperiments indicated that base was important for the reaction (entry 7). So we studied the base effect further.However,v arious organic bases, such as triethylamine (Et 3 N), triisopropylamine (iPr 3 N), N-methylpiperidine andp iperidine,c ould not improvet he yield of 2a (entries 8-11), and inorganic bases (Na 2 CO 3 ,K 2 CO 3 ,N aHCO 3 , NaOH, K 3 PO 4 )f ailed to promote this bifunctionalization reaction with full recovery of 1a (entries [12][13][14][15][16]. Therefore, pyridine was chosen as the base to further study the solvent effect.…”