Highly Substituted Furo[3,4‐d][1,2]oxazines: Gold‐Catalyzed Regiospecific and Diastereoselective 1,3‐Dipolar Cycloaddition of 2‐(1‐Alkynyl)‐2‐alken‐1‐ones with Nitrones

Rapid access: A gold(I)-catalyzed 1,3-dipolar cycloaddition of 2-(1-alkynyl)-2-alken-1-ones with nitrones provides a practical, regiospecific, and stereoselective access to highly substituted fused bicyclic furo[3,4-d][1,2]oxazines under mild conditions (see scheme). These fused heterobicyclic compounds can be readily converted into furans or 3,6-dihydro-2H-1,2-oxazines in a chemoselective fashion.