Effect of reaction solvent on the synthesis of vicinal diamine 2a in microdroplets was thereafter explored following the optimization of the acid catalyst. The results (Table , Entries 10-12, and Table ) demonstrated that the ring opening of 1a by microdroplet chemistry can be realized in all of the tested organic solvents except that 1a was insoluble in methanol. Among the six tested organic solvents, acetonitrile (MeCN), dichloromethane (DCM) and acetone were three of the best solvents for the conversion by organic microdroplets (Table , Entries 1-3) whereas tetrahydrofuran (THF) and ethyl acetate (EtOAc) offered comparable yields of vicinal diamine 2a (Table , Entries 4-5). In addition, the introduction of a moderate amount of water into acetonitrile as a reaction solvent led to a gradually decreased yield of 2a (Table , Entries 13-14) and 3a for both microdroplet and bulk reactor. However, the addition of water did not alter the reaction pathways of the microdroplet and the bulk reactor. Acetonitrile was selected as the reaction solvent considering good yield and low cost.