- Photostimulated Reactions of o-Dihalobenzenes with Nucleophiles Derived from the 2-Naphthyl System. Competition between Electron Transfer, Fragmentation, and Ring Closure Reactions
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The photostimulated reaction of o-dihalobenzenes 2 with 2-naphthoxide ions 1-O gave the substitution product on carbon 1 of the naphthyl moiety with retention of halogen (I, Br, and Cl) 3 as well as the ring closure product benzonaphtholfuran (4), with product 3 being an intermediate in the formation of 4.The products obtained in the photostimulated reaction of 2-naphthalenethiolate ions 1-S with 2 depend on the halogens.When both nucleofugal groups are iodine, only the ring closure product benzonaphthothiophene (10) is obtained.With o-bromoiodobenzene, the photostimulated reaction gave 10 and the substitution product on sulfur with retention of bromine, while with o-chloroiodobenzene the only observed product was the substitution product on sulfur with retention of chlorine.The photostimulated reaction of 2 with 2-naphthaleneselenolate ions 1-Se gave the same amount of cyclized product benzonaphthoselenophene (14) and the substitution product on selenium without retention of halogen 15, although in an overall low yield.It is suggested that all these reactions occur by the SRN1 mechanism.Theoretical studies support the different behavior found with the nucleophiles derived from the 2-naphthyl system.
- Baumgartner, Maria T.,Pierini, Adriana B.,Rossi, Roberto A.
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p. 2593 - 2598
(2007/10/02)
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- The reactivity of oxygen nucleophiles with aryl radicals in the S(RN)1 mechanism
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The photostimulated reaction of 2-naphthoxide ions 1 with o-dihalobenzenes in liquid ammonia gives the halosubstituted product 4 and the cyclized substituted product 5. This is the first report about the coupling of an aromatic σ radical with an oxygen functionality in the chain propagation cycle of the S(RN)1 mechanism.
- Baumgartner,Pierini,Rossi
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p. 2323 - 2326
(2007/10/02)
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