Lithium diisopropylamide solvated by hexamethylphosphoramide: substrate-dependent mechanisms for dehydrobrominations.
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.
Ma
Yun
Y
Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853-1301, USA.
Ramirez
Antonio
A
Singh
Kanwal Jit
KJ
Keresztes
Ivan
I
Collum
David B
DB
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
D006842:Hydrocarbons, Brominated; D011437:Propylamines; D012996:Solutions; D012997:Solvents; C007442:diisopropylamine; D006492:Hempa