Grignard formation and reaction in hydrocarbon media: The effect of catalytic butyldiglyme, TMEDA and ether

ORGN 104

Robert Holman, holmrobe@isu.edu, Courtney Tracy, and Mary Anderson. Department of Chemistry, Idaho State University, Box 8023, Pocatello, ID 83209
Grignard reactions are typically conducted in ether solvents which have long term storage, disposal and other environmental problems and, in addition, are hygroscopic. The generation of Grignard reagents in hydrocarbon media circumvents these environmental issues and concerns regarding accidental water are reduced. Ether removal from pre-prepared Grignard reagents and replacement with cyclohexane followed by reaction with an array of substrates generates a modest yield of the expected products. When catalyzed with 0.1 equivalents of butyldiglyme, TMEDA, or DEE the yields are comparable to those from reactions in pure DEE. Grignard formation and subsequent reaction in cyclohexane catalyzed by butyldiglyme, TMEDA, or DEE result in high yields of the expected products. Mechanistic insight from NMR spectroscopy centering on the nature of this catalysis indicates that this modified chemistry is mechanistically related to, but distinct from, classic Grignard reactions performed in DEE.