title: Lithium diisopropylamide solvated by hexamethylphosphoramide: substrate-dependent mechanisms for dehydrobrominations.
abstract: Lithium diisopropylamide-mediated dehydrobrominations of exo-2-bromonorbornane, 1-bromocyclooctene, and cis-4-bromo-tert-butylcyclohexane were studied in THF solutions and THF solutions with added hexamethylphosphoramide (HMPA). Rate studies reveal a diverse array of mechanisms based on mono-, di-, and trisolvated monomers as well as triple ions. The results are contrasted with analogous eliminations in THF in the absence of HMPA.
authors.affiliation: Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853-1301, USA.
authors.forename: Yun
authors.initials: Y
authors.lastname: Ma
authors.forename: Antonio
authors.initials: A
authors.lastname: Ramirez
authors.forename: Kanwal Jit
authors.initials: KJ
authors.lastname: Singh
authors.forename: Ivan
authors.initials: I
authors.lastname: Keresztes
authors.forename: David B
authors.initials: DB
authors.lastname: Collum
mesh_terms: D006492:Hempa / Q000737:chemistry*; D006842:Hydrocarbons, Brominated / Q000737:chemistry*; D015394:Molecular Structure; D011437:Propylamines / Q000737:chemistry*; D012996:Solutions; D012997:Solvents / Q000737:chemistry*; D013329:Structure-Activity Relationship
chemical_list: D006842:Hydrocarbons, Brominated; D011437:Propylamines; D012996:Solutions; D012997:Solvents; C007442:diisopropylamine; D006492:Hempa