A Highly Stereocontrolled, One-Pot Approach toward Pyrrolobenzoxazinones and Pyrroloquinazolinones through a Lewis Acid-Catalyzed [3 + 2]-Cycloannulation Process

We report herein a stereocontrolled
[3 + 2]-cycloheteroannulation
of bis-silyl dienediolate 1 with 2-aminobenzoic acid-
and 2-aminobenzamide-derived imines to furnish highly substituted
pyrrolo­[1,2-a]­benzoxazinones 3 and pyrrolo­[1,2-a]­quinazolinones 4, respectively, in good overall
yields. This one-pot process rapidly generates molecular complexity
and comprises a Lewis acid-catalyzed, vinylogous Mannich reaction
of 1 followed by an intramolecular N,O-acetal- and N,N-aminal formation, respectively, which proceeds with good to excellent
stereocontrol.