Formation and isomerization of 2-azaallyllithium reagents in deprotonations of N-benzyl ketimines containing .alpha.-protons Academic Article uri icon

abstract

  • Deprotonation of the N-benzylimine of 3-pentanone by lithium diisopropylamide (LDA) in tetrahydrofuran occurs at the benzylic position to give a 2-azaallyllithium reagent in high yield. On standing, the 2-azaallyllithium reagent isomerizes to a 1-azaallyllithium reagent. The N-benzylimine of 2-butanone can be similarly deprotonated by LDA at the benzylic position in competition with deprotonation at the α-positions to give a 2-azaallyllithium reagent in up to 22% yield. The N-benzylimine of acetone is not appreciably deprotonated at the benzylic position by LDA. Kinetic studies of the isomerization of 2-azaallyl- to 1-azaallyilithium reagent from the 3-pentanone imine suggest that this reaction proceeds by a protonation-deprotonation sequence. © 1985, American Chemical Society. All rights reserved.

author list (cited authors)

  • Smith, J. K., Bergbreiter, D. E., & Newcomb, M.

citation count

  • 13

publication date

  • November 1985