Main Group Conjugated Organic Anion Chemistry. 3. Application of Magnesium-Anthracene Compounds in the Synthesis of Grignard Reagents

Article abstract of DOI:10.1021/jo00249a002

Reaction of magnesium-arene compounds, , 1, and some silylanthracene, and/or tertiary amine analogues, with benzylic and allylic chlorides or bromides, and (Me3Si)3CCl, afford Grignard reagents, RMgX, in modest to high yield for chlorides and negligible to high yield for the bromides, in THF, toluene, and hexane at -10 to 20 deg C.Novel benzylic-type Grignard reagents prepared in high yield include those of 9-(chloromethyl)anthracene, 2-(chloromethyl)pyridine and 8-(chloro(or bromo)methyl)quinoline, and poly-Grignard reagents derived from 1,8-bis(chloromethyl)naphthalene, 2,2'-bis(chloromethyl)-1,1'-binaphthyl, and 1,3,5,-tris(chloro(or bromo)methyl)benzene.Grignard reagent formation occurs via electron-transfer reactions.Aryl and alkyl halides yield mainly products derived from addition of the halide across the 9,10-positions of the anthracenes, via nucleophilic substitution or collapse of a diradical cage 2+, (anthracene)-anion radical, RX-anion radical.>