98515-22-1Relevant academic research and scientific papers
Mechanism of Reaction between Grignard Reagents and Nitroarenes. Product Distribution and Relative Reactivities of Grignard Reagents with Nitronaphthalene System
Bartoli, Giuseppe,Bosco, Marcella,Cantagalli, Gabriele,Dalpozzo, Renato,Ciminale, Francesco
, p. 773 - 780 (2007/10/02)
The reaction of 2-methoxy-1-nitronaphthalene with various Grignard reagents has been examined.Alkylmagnesium halides such as CH3MgBr, PhCH2MgBr, PhCH2CH2MgBr, C2H5MgBr, and i-C3H7MgBr give 1,6-addition products almost exclusively, while PhMgBr gives instead comparable amounts of 1,4-addition and reductive 1,2-addition products.Hex-5-enylmagnesium bromide reacts giving two 1,6-addition products, one containing a straight chain and the other one a cyclized alkyl fragment, where the ratio of the two decreases with decreasing temperature.The reactivity order (i-C3H7 > PhCH2 ca.C2H5 > PhCH2CH2 > CH3) established by competitive reactions along with the reactivity pattern shown by hex-5-enylmagnesium bromide was taken as clear evidence for a single-electron transfer (s.e.t.) process.A mechanism involving s.e.t. from Grignard reagent to nitroarene followed by collapse within the solvent cage of the two radicals thus formed (geminate combination) or, to a lesser extent, out of the cage (non-geminate combination), is suggested.The reaction of 1-nitronaphthalene with methyl-, isopropyl- and hex-5-enyl-magnesium bromides indicates that the distribution of isomeric 2- and 4-alkylated products is determined by the reactivity of the ring positions for both geminate and non-geminate combination.No firm mechanistic conclusions were reached regarding the reaction of PhMgBr.
