A DFT study on the mechanism of gold(III)-catalyzed synthesis of highly substituted furans via [3,3]-sigmatropic rearrangements and/or [1,2]-acyloxy migration based on propargyl ketones

作者：Fang, Ran^*; Yang, Lizi; Wang, Yongcheng

来源：Organic and Biomolecular Chemistry, 2011, 9(8): 2760-2770.

DOI：10.1039/c0ob01098g

• GOLD-CATALYZED CYCLOISOMERIZATION
• POLARIZABLE CONTINUUM MODEL
• DENSITY-FUNCTIONAL THEORY
• FACE-SELECTIVE PLATINUM
• EFFICIENT SYNTHESIS
• GOLD(I)-CATALYZED SYNTHESIS
• 1,2-ALLENYL KETONES
• ENYNYL ACETATES
• BOND FORMATION
• AB-INITIO

The mechanisms of gold(III)-catalyzed synthesis of highly substituted furans via [3,3]-sigmatropic rearrangements and/or [1,2]-acyloxy migration based on propargyl ketones have been investigated using density functional theory calculations at BHandHLYP/6-31G(d,p) (SDD for Au) level of theory. Solvent effects on these reactions were explored using calculations that included a polarizable continuum model (PCM) for the solvent (toluene). Two plausible pathways that lead to the formation of Au(III) vinyl carbenoid and an allenyl structure through [3,3]-sigmatropic rearrangements, [1,2]-acyloxy migration via oxirenium and dioxolenylium were performed. Our calculated results suggested: (1) the major pathway of the cycle causes an initial Rautenstrauch-type [1,2]-migration via oxirenium to form an Au(III) vinyl carbenoid. Subsequent cycloisomerization of this intermediate then provides the corresponding furan whether for the methyl-substituted propargylic acetates or the phenyl-substituted propargylic acetates; (2) for the methyl-substituted propargylic acetates, the formation of Au(III) vinyl carbenoid structures was the rate-determining step. However, intramolecular nucleophilic attack and subsequent cycloisomerization to give the final product was rate-determining for the phenyl-substituted propargylic acetates. The computational results are consistent with the experimental observations of Gevorgyan, et al. for gold(III)-catalyzed synthesis of highly substituted furans based on propargyl ketones.

• 出版日期2011
• 单位兰州大学; 西北师范大学