A Tandem Ring‐Opening/Michael Addition/Ring‐Closure Sequence for the Regiospecific Synthesis of 5‐Hydroxy‐4,5‐dihydroisoxazoles

An effective and highly regiospecific strategy for the synthesis of 5-hydroxy-4,5-dihydroisoxazoles is described via a tandem reaction including ring-opening, Michael addition, and ring-closure in one pot under mild conditions. Diverse structural 5-hydroxy-4,5-dihydroisoxazoles were afforded in up to 96% yield for 21 examples. This strategy is highly efficient, environmentally friendly, and metal free.