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A theoretical study on the trans-addition intramolecular hydroacylation of 4-alkynals catalyzed by cationic rhodium complexes.
J Org Chem. 2008 Apr 04; 73(7):2649-55.JO

Abstract

The mechanism of the intramolecular hydroacylation reaction of 4-alkynals is studied for a 4-pentynal-[Rh(PH2CH2CH2PH2)]+ model system using MP2 calculations. The endo-cyclization to form a rhodacyclohexenone intermediate is kinetically less favorable than the exo-cyclization to form a rhodacyclopentanone intermediate. The kinetic preference toward the endo-cyclization is found to be enhanced by complexation of donor ligands (H2CO, NCH, and HCCH). The formation of cyclopentenone product proceeds via reductive elimination from one of the two rhodacyclohexenone intermediates, whereas the formation of cyclobutanone product from the two rhodacyclopentanone intermediates requires high activation energy. Addition of an acetylene stabilizes the highly electron-poor rhodacyclopentanone intermediate generated from exo-cyclization and leads to an insertion to give [4 + 2] annulation product, cyclohexenone. The role of a coordinating acetone solvent in the formation of cyclopentenone product is also discussed.

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Publisher Full Text (DOI)

Authors+Show Affiliations

Chung LW
Department of Chemistry and Open Laboratory of Chirotechnology of the Institute of Molecular Technology for Drug Discovery and Synthesis, The Hong Kong University of Science & Technology, Clear Water Bay, Kowloon, Hong Kong, China.
Wiest O
No affiliation info available
Wu YD
No affiliation info available

MeSH

AcylationAldehydesAlkynesCatalysisCationsComputer SimulationCyclizationKetonesKineticsModels, ChemicalMolecular StructureOrganometallic CompoundsRhodiumStereoisomerism

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

18324834

Citation

Chung, Lung Wa, et al. "A Theoretical Study On the Trans-addition Intramolecular Hydroacylation of 4-alkynals Catalyzed By Cationic Rhodium Complexes." The Journal of Organic Chemistry, vol. 73, no. 7, 2008, pp. 2649-55.
Chung LW, Wiest O, Wu YD. A theoretical study on the trans-addition intramolecular hydroacylation of 4-alkynals catalyzed by cationic rhodium complexes. J Org Chem. 2008;73(7):2649-55.
Chung, L. W., Wiest, O., & Wu, Y. D. (2008). A theoretical study on the trans-addition intramolecular hydroacylation of 4-alkynals catalyzed by cationic rhodium complexes. The Journal of Organic Chemistry, 73(7), 2649-55. https://doi.org/10.1021/jo702582j
Chung LW, Wiest O, Wu YD. A Theoretical Study On the Trans-addition Intramolecular Hydroacylation of 4-alkynals Catalyzed By Cationic Rhodium Complexes. J Org Chem. 2008 Apr 4;73(7):2649-55. PubMed PMID: 18324834.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - A theoretical study on the trans-addition intramolecular hydroacylation of 4-alkynals catalyzed by cationic rhodium complexes. AU - Chung,Lung Wa, AU - Wiest,Olaf, AU - Wu,Yun-Dong, Y1 - 2008/03/07/ PY - 2008/3/8/pubmed PY - 2008/6/20/medline PY - 2008/3/8/entrez SP - 2649 EP - 55 JF - The Journal of organic chemistry JO - J Org Chem VL - 73 IS - 7 N2 - The mechanism of the intramolecular hydroacylation reaction of 4-alkynals is studied for a 4-pentynal-[Rh(PH2CH2CH2PH2)]+ model system using MP2 calculations. The endo-cyclization to form a rhodacyclohexenone intermediate is kinetically less favorable than the exo-cyclization to form a rhodacyclopentanone intermediate. The kinetic preference toward the endo-cyclization is found to be enhanced by complexation of donor ligands (H2CO, NCH, and HCCH). The formation of cyclopentenone product proceeds via reductive elimination from one of the two rhodacyclohexenone intermediates, whereas the formation of cyclobutanone product from the two rhodacyclopentanone intermediates requires high activation energy. Addition of an acetylene stabilizes the highly electron-poor rhodacyclopentanone intermediate generated from exo-cyclization and leads to an insertion to give [4 + 2] annulation product, cyclohexenone. The role of a coordinating acetone solvent in the formation of cyclopentenone product is also discussed. SN - 0022-3263 UR - https://www.unboundmedicine.com/medline/citation/18324834/A_theoretical_study_on_the_trans_addition_intramolecular_hydroacylation_of_4_alkynals_catalyzed_by_cationic_rhodium_complexes_ DB - PRIME DP - Unbound Medicine ER -