Palladium-Catalyzed Sequential Hydroamination and Hydroxylation of 1,3-Enynes with 2-Aminophenols

We herein present an atom- and step-economic palladium-catalyzed sequential hydroamination and hydroxylation of readily available 1,3-enynes with 2-aminophenol derivatives. This strategy provides an efficient and redox-neutral route for the synthesis of 3,4-dihydro-2H-1,4-benzoxazines with good to high yields, demonstrating broad substrate scope, excellent regioselectivities, and high E-selectivities. Unlike prior reports, no acidic or basic additives are required for this process. The practicality of this protocol is further highlighted by the gram-scale reaction and rapid access to functionalized 3,4-dihydro-2H-1,4-benzoxazines.