Focused ortho-Lithiation and Functionalization of p-Bromo- and p-Iodoanisole
By use of the strategy for ortho-lithiation (DoM) that conceptually diminishes the pKA difference between the ortho-H of the substrate and the conjugate acid of the metalating agent, effective metalation of bromine and iodine bearing aryl substrates can be carried out. As a set of prototypes, p-bromoanisole (p-BrA) and p-iodoanisole (p-IA) have been successfully ortho-metalated in promoted hydrocarbon media using ortho-lithiodimethylbenzylamine (o-LiDMBA) as the metalating agent. No hint of exchange of either halogen was noted using these conditions. These studies add to the emerging evidence of a hitherto unidentified acidifying effect on the proton(s) ortho- to a directing metalation group (DMG) by both a p-iodo and a p-bromo substituent.
Slocum,Jennings, John A.,Reinscheld, Thomas K.,Whitley, Paul E.
p. 4400 - 4406
(2018/09/10)
Metalations utilizing aryllithiums; ortho-functionalization of p-bromoanisole (pBrA)
An ortho-metalation protocol has been developed, which permits the survival of a bromine substituent in p-bromoanisole. Eight derivatives of the generated ortho-lithiated intermediate have been prepared. A neglected metalation concept is being explored here; one which proposes that minimizing the pKa difference between the aryl substrate and the conjugate acid of the metalating agent will lead to a regiospecific and selective metalation process.
Slocum,Reece, Troy L.,Sandlin, Rebecca D.,Reinscheld, Thomas K.,Whitley, Paul E.
experimental part
p. 1593 - 1595
(2009/06/18)
More Articles about upstream products of 94622-89-6