Concise synthesis of α-substituted 2-benzofuranmethamines and other 2-substituted benzofurans via α-substituted 2-benzofuranmethyl carbocation intermediates

dc.contributor.authorWongsa, Nikhom
dc.contributor.authorSommart, Ubonta
dc.contributor.authorRitthiwigrom, Thunwadee
dc.contributor.authorYazici, Arife
dc.contributor.authorKanokmedhakul, Somdej
dc.contributor.authorKanokmedhakul, Kwanjai
dc.contributor.authorWillis, Anthony
dc.contributor.authorPyne, Stephen G
dc.date.accessioned2015-12-13T22:16:16Z
dc.date.issued2013
dc.date.updated2016-02-24T08:57:42Z
dc.description.abstractPropargyl amines 4, where R3 is aryl, undergo 5-exo-dig cyclization reactions under relatively mild conditions (AgNO3, DMF, 60 C, 1 h) to give 3-amino-2,3-dihydro-2-arylmethylidenebenzofurans 5 (R 3 = aryl). In contrast, substrates where R3 is alkyl undergo competing 6-endo-dig and 5-exo-dig cyclization processes. The hydroxymethyl substrate 4 (R3 = CH2OH), however, was smoothly converted to its corresponding 5-exo-dig cyclization product 5, likely due to the assistance of the primary hydroxyl group in the 5-exo-dig cyclization process by silver cation coordination. Under more enforcing conditions (AgNO3, DMF, 100 C, 18 h), the initially formed products 5 undergo a 1,3-allylic rearrangement to their corresponding 2-substituted benzofuran derivatives 6. This rearrangement can also be effected by treating 5 with AgNO3 in DMF at 100 C for 18 h or BF3·Et 2O at rt. 2-(3-Butenyl)benzofurans 7 (Nu = allyl) can be prepared by treatment of 5 with BF3·Et2O and allyltributylstannane. Furan and MeOH could also be employed as external nucleophiles in these BF3·Et2O-promoted reactions.
dc.identifier.issn0022-3263
dc.identifier.urihttp://hdl.handle.net/1885/70777
dc.publisherAmerican Chemical Society
dc.sourceJournal of Organic Chemistry
dc.subjectKeywords: 1 ,3-allylic rearrangement; Allyltributylstannane; Benzofurans; Carbocations; Concise synthesis; Cyclization products; Cyclization reactions; Hydroxyl groups; Propargyl; Silver cations; Chemical compounds; Methanol; Substrates; Cyclization; 1 (2 benzylide
dc.titleConcise synthesis of α-substituted 2-benzofuranmethamines and other 2-substituted benzofurans via α-substituted 2-benzofuranmethyl carbocation intermediates
dc.typeJournal article
local.bibliographicCitation.issue3
local.bibliographicCitation.lastpage1148
local.bibliographicCitation.startpage1138
local.contributor.affiliationWongsa, Nikhom, Khon Kaen University
local.contributor.affiliationSommart, Ubonta, Prince of Songkla University
local.contributor.affiliationRitthiwigrom, Thunwadee, University of Wollongong
local.contributor.affiliationYazici, Arife, University of Wollongong
local.contributor.affiliationKanokmedhakul, Somdej, Khon Kaen University
local.contributor.affiliationKanokmedhakul, Kwanjai, Khon Kaen University
local.contributor.affiliationWillis, Anthony, College of Physical and Mathematical Sciences, ANU
local.contributor.affiliationPyne, Stephen G, University of Wollongong
local.contributor.authoremailu8512028@anu.edu.au
local.contributor.authoruidWillis, Anthony, u8512028
local.description.embargo2037-12-31
local.description.notesImported from ARIES
local.identifier.absfor030503 - Organic Chemical Synthesis
local.identifier.absseo970103 - Expanding Knowledge in the Chemical Sciences
local.identifier.ariespublicationf5625xPUB2411
local.identifier.citationvolume78
local.identifier.doi10.1021/jo302554v
local.identifier.scopusID2-s2.0-84873325933
local.identifier.thomsonID000314558300033
local.identifier.uidSubmittedByf5625
local.type.statusPublished Version

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