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Isotope effects, dynamic matching, and solvent dynamics in a Wittig reaction. Betaines as bypassed intermediates.

ABSTRACT: The mechanism of the Wittig reaction of anisaldehyde with a stabilized ylide was studied by a combination of (13)C kinetic isotope effects, conventional calculations, and molecular dynamics calculations in a cluster of 53 THF molecules. The isotope effects support a cycloaddition mechanism involving two sequential transition states associated with separate C-C and P-O bond formations. However, the betaine structure in between the two transition states is bypassed as an equilibrated intermediate in most trajectories. The role of the dynamics of solvent equilibration in the nature of mechanistic intermediates is discussed.

SUBMITTER: Chen Z

PROVIDER: S-EPMC4183629 | biostudies-literature | 2014 Sep

REPOSITORIES: biostudies-literature

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Isotope effects, dynamic matching, and solvent dynamics in a Wittig reaction. Betaines as bypassed intermediates.

Chen Zhuo Z Nieves-Quinones Yexenia Y Waas Jack R JR Singleton Daniel A DA

Journal of the American Chemical Society 20140912 38

The mechanism of the Wittig reaction of anisaldehyde with a stabilized ylide was studied by a combination of (13)C kinetic isotope effects, conventional calculations, and molecular dynamics calculations in a cluster of 53 THF molecules. The isotope effects support a cycloaddition mechanism involving two sequential transition states associated with separate C-C and P-O bond formations. However, the betaine structure in between the two transition states is bypassed as an equilibrated intermediate ...[more]

PMID: 25208686

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