TfOH-Catalyzed Regioselective Alkylation of Hydroxybenzotriazole with Diazo Compounds and Further Base-Facilitated Elimination under Batch and Flow Conditions

An efficient and fascinating strategy has been devised for the construction of N-hydroxybenzotriazole (HOBt) derivatives and alpha-ketoesters through TfOH-catalyzed regioselective alkylation of N-hydroxybenzotriazole (HOBt) and one-pot base-facilitated elimination of alkylation products process under batch and flow conditions. It thus provides an expedient approach to access a range of HOBt derivatives and alpha-ketoesters in good yields with high regioselectivity under mild conditions. Using flow process, less reacting time, being more environment-friendly, and process continuity ensuring higher operation safety are achieved, highlighting the practicality of the developed system. A TfOH-catalyzed regioselective alkylation of hydroxybenzotriazole (HOBt) and one-pot base-facilitated elimination of alkylation products under batch and flow conditions were described. The reaction gave the corresponding HOBt derivatives and alpha-ketoesters in consistently good yields with excellent regioselectivity under mild conditions. image