Sc(OTf)3-catalyzed alkyne-carbonyl metathesis-initiated cyclization for accessing naphtho[2,1-b]furan-1-ones under microwave heating

A new microwave-promoted Sc(OTf)3-catalyzed alkyne-carbonyl metathesis-initiated cyclization of 1-alkynylnaphthalen-2-ols with ninhydrin is reported, furnishing a wide range of naphtho[2,1-b]furan-1-ones with a quaternary center in good yields. Exchang ninhydrin for 5,5-dihydroxypyrimidine-2,4,6(1H,3H,5H)-trione resulted in functionalized pyrimidine-2,4,6-trione-containing naphtho[2,1-b]furan-1-ones. The catalytic cyclization protocol has attractive characteristics of high atom utilization, good compatibility with different types of substituents, and the efficient control of regiochemistry.