Reactions of nitroarenes with secondary and tertiary carbanions bearing both a leaving group and electron‐withdrawing group: An approach to dihydronaphth[2,1‐c]isoxazole N‐oxides and dihydroisoxazolo[4,3‐f]quinoline N‐oxides

Abstract

Abstract2‐Nitronaphthalene (1) and 6‐nitroquinoline (2) underwent direct cyclocondensation with secondary and tertiary carbanions derived from a methylene and methine group bearing both a leaving group and electron‐withdrawing group (e.g., methyl chloroacetate, ethyl chloroacetate, chloroacetonitrile, methyl 2‐chloropropionate, ethyl 2‐chloropropionate and 2‐chloropropionitrile) in the sodium hydride/N,N‐dimethylformamide system at low temperature, giving the corresponding dihydronaphth[2,1‐c]isoxazole N‐oxides 3 and dihy‐droisoxazolo[4,3‐f]quinoline N‐oxides 4. On the other hand, nitroarenes 1 and 2 reacted with secondary carbanions in the sodium hydride/tetrahydrofuran system to yield the corresponding conventional vicarious nucleophilic substitution (VNS) products 5 and 6.