title: Elucidating the mechanism of reversible oxiranations via magnetization transfer spectroscopy.
abstract: The reversible [2 + 1] cycloadditions between an N,N'-diamidocarbene (DAC) and eight aldehydes were examined using NMR spectroscopy. Variable temperature magnetization transfer experiments revealed higher exchange rates and lower activation barriers when electron-deficient aldehydes were employed. Likewise, competitive equilibrium studies indicated a thermodynamic preference for electron-deficient aryl and sterically unhindered alkyl aldehydes compared to more electron-rich or bulkier substrates. Collectively, these and other data collected were consistent with the oxiranation process proceeding in an asynchronous manner.
authors.affiliation: Department of Chemistry and Biochemistry, The University of Texas at Austin, Austin, Texas 78712, USA.
authors.forename: Daniel T
authors.initials: DT
authors.lastname: Chase
authors.forename: Jonathan P
authors.initials: JP
authors.lastname: Moerdyk
authors.forename: Christopher W
authors.initials: CW
authors.lastname: Bielawski