Domino [3+2+1] Heteroannulation for Stereoselective Synthesis of Anti-Pyrazolo[3,4-d][1,3]oxazines

Polysubstituted anti-pyrazolo[3,4-d][1,3]oxazines (III) are efficiently and stereoselectively obtained by three-component one-pot domino reaction of arylglyoxals with pyrazol-5-amines under mild reaction conditions.