Diastereoselective Palladium-Catalyzed [4+1] Cycloadditions of 4-Vinyl-1,4-dihydro-2H-3,1-benzoxazin-2-ones with In Situ Formed Carbenes

Herein, we present a palladium-catalyzed tandem [4+1] cyclo­addition of 4-vinyl-1,4-dihydro-2H-3,1-benzoxazin-2-ones with ­N-tosyl­hydrazones. The reaction is accomplished by merging the in situ generated aza-ortho-quinone methides (aza-o-QMs) with nucleophilic carbenes. This method enables the construction of diverse indolines with broad functional group compatibility in good yields with high levels of diastereoselectivity under mild conditions.