Diverse reactivity of 2-formylphenylboronic acid with secondary amines: synthesis of 3-amino-substituted benzoxaboroles

In the reaction of 2-formylphenylboronic acid with secondary amines different products are formed depending on the structure of the amines. For aliphatic amines the reaction proceeds with the formation of 3-amino-substituted benzoxaboroles or with the formation of complexed boroxins. A crystal structure of the benzoxaborole with a thiomorpholinyl substituent was determined.