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Article: DFT study on the mechanism and regioselectivity of gold(I)-catalyzed synthesis of highly substituted furans based on 1-(1-alkynyl)cyclopropyl ketones with nucleophiles

TitleDFT study on the mechanism and regioselectivity of gold(I)-catalyzed synthesis of highly substituted furans based on 1-(1-alkynyl)cyclopropyl ketones with nucleophiles
Authors
Issue Date2009
PublisherAmerican Chemical Society. The Journal's web site is located at http://pubs.acs.org/organometallics
Citation
Organometallics, 2009, v. 28 n. 3, p. 741-748 How to Cite?
AbstractThe mechanism and regioselectivity of gold(I)-catalyzed synthesis of highly substituted furans based on l-(l-alkynyl)cyclopropyl ketones with nucleophiles have been investigated using density functional theory calculations done at the BH and HLYP/6-31G(d, p) (SDD for Au) level of theory. Solvent effects on these reactions have been explored by calculations that included a polarizable continuum model (PCM) for the solvent (dichloromethane). Our calculations suggest that the first step of the cycle is the cyclization of the carbonyl oxygen onto the triple bond to form a new and stable five-membered resonance structure of an oxonium ion and a carbocation intermediate. Furthermore, the seven-membered carbocation intermediate proposed by Zhang and Schmalz was found and characterized as a transition structure on the potential energy surface. The attack of the carbonyl oxygen to the gold-coordinated alkynes results in the formation of a resonance structure intermediate, which upon subsequent trapping with alcohols followed by migration of a hydrogen atom results in the formation of the final products and regeneration of the catalyst. The key reaction step is the attack of the oxygen atom of the CH 3OH on the C - C σ bond of the cyclopropane moiety to yield new organogold intermediates through formation of a C - O bond and cleavage of a C - C bond. The cleavage of the C - C bond is strongly favored kinetically in the case of the C 1 - C 2 bond and required only 19.8 kcal/mol of energy, while the activation energy for cleavage of the C 1 - C 3 bond was found to be 31.8 kcal/mol and indicates that the ring-opening cycloisomerization for cyclopropyl ketones has high regioselectivity. Our computational results are consistent with the experimental observations of Zhang and Schmalz for the gold(I)-catalyzed synthesis of highly substituted furans based on l-(l-alkynyl)cyclopropyl ketones with nucleophiles. © 2009 American Chemical Society.
Persistent Identifierhttp://hdl.handle.net/10722/58371
ISSN
2015 Impact Factor: 4.186
2015 SCImago Journal Rankings: 2.043
ISI Accession Number ID
Funding AgencyGrant Number
National Natural Science Foundation of China20673149
Natural Science Foundation of Guangdong Province7003709
Hong Kong Research Grants CouncilHKU/7040/06P
Funding Information:

We gratefully acknowledge the National Natural Science Foundation of China (Grant No. 20673149), the Natural Science Foundation of Guangdong Province (Grant No. 7003709) to C.Y.Z., and the Hong Kong Research Grants Council (HKU/7040/06P) to D.L.P. for the financial support of this research. We are grateful to the reviewers for their invaluable suggestions and Prof. Zhenyang Lin for his helpful discussions.

References

 

DC FieldValueLanguage
dc.contributor.authorFang, Ren_HK
dc.contributor.authorSu, CYen_HK
dc.contributor.authorZhao, Cen_HK
dc.contributor.authorPhillips, DLen_HK
dc.date.accessioned2010-05-31T03:29:08Z-
dc.date.available2010-05-31T03:29:08Z-
dc.date.issued2009en_HK
dc.identifier.citationOrganometallics, 2009, v. 28 n. 3, p. 741-748en_HK
dc.identifier.issn0276-7333en_HK
dc.identifier.urihttp://hdl.handle.net/10722/58371-
dc.description.abstractThe mechanism and regioselectivity of gold(I)-catalyzed synthesis of highly substituted furans based on l-(l-alkynyl)cyclopropyl ketones with nucleophiles have been investigated using density functional theory calculations done at the BH and HLYP/6-31G(d, p) (SDD for Au) level of theory. Solvent effects on these reactions have been explored by calculations that included a polarizable continuum model (PCM) for the solvent (dichloromethane). Our calculations suggest that the first step of the cycle is the cyclization of the carbonyl oxygen onto the triple bond to form a new and stable five-membered resonance structure of an oxonium ion and a carbocation intermediate. Furthermore, the seven-membered carbocation intermediate proposed by Zhang and Schmalz was found and characterized as a transition structure on the potential energy surface. The attack of the carbonyl oxygen to the gold-coordinated alkynes results in the formation of a resonance structure intermediate, which upon subsequent trapping with alcohols followed by migration of a hydrogen atom results in the formation of the final products and regeneration of the catalyst. The key reaction step is the attack of the oxygen atom of the CH 3OH on the C - C σ bond of the cyclopropane moiety to yield new organogold intermediates through formation of a C - O bond and cleavage of a C - C bond. The cleavage of the C - C bond is strongly favored kinetically in the case of the C 1 - C 2 bond and required only 19.8 kcal/mol of energy, while the activation energy for cleavage of the C 1 - C 3 bond was found to be 31.8 kcal/mol and indicates that the ring-opening cycloisomerization for cyclopropyl ketones has high regioselectivity. Our computational results are consistent with the experimental observations of Zhang and Schmalz for the gold(I)-catalyzed synthesis of highly substituted furans based on l-(l-alkynyl)cyclopropyl ketones with nucleophiles. © 2009 American Chemical Society.en_HK
dc.languageengen_HK
dc.publisherAmerican Chemical Society. The Journal's web site is located at http://pubs.acs.org/organometallicsen_HK
dc.relation.ispartofOrganometallicsen_HK
dc.titleDFT study on the mechanism and regioselectivity of gold(I)-catalyzed synthesis of highly substituted furans based on 1-(1-alkynyl)cyclopropyl ketones with nucleophilesen_HK
dc.typeArticleen_HK
dc.identifier.openurlhttp://library.hku.hk:4550/resserv?sid=HKU:IR&issn=0276-7333&volume=28&spage=741&epage=748&date=2009&atitle=DFT+Study+on+the+Mechanism+and+Regioselectivity+of+Gold(I)-Catalyzed+Synthesis+of+Highly+Substituted+Furans+Based+on+1-(1-Alkynyl)cyclopropyl+Ketones+with+Nucleophilesen_HK
dc.identifier.emailPhillips, DL:phillips@hku.hken_HK
dc.identifier.authorityPhillips, DL=rp00770en_HK
dc.description.naturelink_to_subscribed_fulltext-
dc.identifier.doi10.1021/om800751uen_HK
dc.identifier.scopuseid_2-s2.0-61849106583en_HK
dc.identifier.hkuros160823en_HK
dc.relation.referenceshttp://www.scopus.com/mlt/select.url?eid=2-s2.0-61849106583&selection=ref&src=s&origin=recordpageen_HK
dc.identifier.volume28en_HK
dc.identifier.issue3en_HK
dc.identifier.spage741en_HK
dc.identifier.epage748en_HK
dc.identifier.isiWOS:000262913600012-
dc.publisher.placeUnited Statesen_HK
dc.identifier.scopusauthoridFang, R=10144173000en_HK
dc.identifier.scopusauthoridSu, CY=7402820091en_HK
dc.identifier.scopusauthoridZhao, C=7403563836en_HK
dc.identifier.scopusauthoridPhillips, DL=7404519365en_HK

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