Room-Temperature B(OAc)₃-Promoted Diels–Alder Reaction of Juglone with Styrenes: Total Syntheses of Tetrangulol and Anhydrolandomycinone

The Diels–Alder reaction of juglone with various styrenes in the presence of 2,3-dichloro-5,6-dicyanobenzoquinone (DDQ) was promoted by B­(OAc)₃ at room temperature. The reaction proceeded smoothly and gave the products in a good yield and with excellent regioselectivity. This strategy was applied to the total syntheses of tetrangulol and anhydrolandomycinone.