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Mechanism and transition-state structures for nickel-catalyzed reductive alkyne-aldehyde coupling reactions.

ABSTRACT: The mechanism of nickel-catalyzed reductive alkyne-aldehyde coupling reactions has been investigated using density functional theory. The preferred mechanism involves oxidative cyclization to form the nickeladihydrofuran intermediate followed by transmetalation and reductive elimination. The rate- and selectivity-determining oxidative cyclization transition state is analyzed in detail. The d --> pi*(perpendicular) back-donation stabilizes the transition state and leads to higher reactivity for alkynes than alkenes. Strong Lewis acids accelerate the couplings with both alkynes and alkenes by coordinating with the aldehyde oxygen in the transition state.

SUBMITTER: McCarren PR

PROVIDER: S-EPMC2824658 | biostudies-literature | 2009 May

REPOSITORIES: biostudies-literature

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Mechanism and transition-state structures for nickel-catalyzed reductive alkyne-aldehyde coupling reactions.

McCarren P R PR Liu Peng P Cheong Paul Ha-Yeon PH Jamison Timothy F TF Houk K N KN

Journal of the American Chemical Society 20090501 19

The mechanism of nickel-catalyzed reductive alkyne-aldehyde coupling reactions has been investigated using density functional theory. The preferred mechanism involves oxidative cyclization to form the nickeladihydrofuran intermediate followed by transmetalation and reductive elimination. The rate- and selectivity-determining oxidative cyclization transition state is analyzed in detail. The d --> pi*(perpendicular) back-donation stabilizes the transition state and leads to higher reactivity for a ...[more]

PMID: 19397371

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