Breaking the tert-Butyllithium Contact Ion Pair: A Gateway to Alternate Selectivity in Lithiation Reactions. Academic Article uri icon

abstract

  • The effects of Lewis basic phosphoramides on the aggregate structure of t-BuLi have been investigated in detail by NMR and DFT methods. It was determined that hexamethylphosphoramide (HMPA) can shift the equilibrium of t-BuLi to include the triple ion pair (t-Bu-Li-t-Bu)-/HMPA4Li+ which serves as a reservoir for the highly reactive separated ion pair t-Bu-/HMPA4Li+. Because the Li-atom's valences are saturated in this ion pair, the Lewis acidity is significantly decreased; in turn, the basicity is maximized which allowed for the typical directing effects within oxygen heterocycles to be overridden and for remote sp3 C-H bonds to be deprotonated. Furthermore, these newly accessed lithium aggregation states were leveraged to develop a simple -lithiation and capture protocol of chromane heterocycles with a variety of alkyl halide electrophiles in good yields.

published proceedings

  • J Am Chem Soc

altmetric score

  • 36.45

author list (cited authors)

  • Crockett, M. P., Pia, J., Gogoi, A. R., Lalisse, R. F., Nguyen, A. V., Gutierrez, O., & Thomas, A. A.

citation count

  • 1

complete list of authors

  • Crockett, Michael P||Piña, Jeanette||Gogoi, Achyut Ranjan||Lalisse, Remy F||Nguyen, Andrew V||Gutierrez, Osvaldo||Thomas, Andy A

publication date

  • May 2023