211491-20-2Relevant articles and documents
Synthesis of novel oxygen heterocycles: 1,10-dioxa-cyclopenta[a]fluorene and benzo[b]naphtho[2, 1-d]furans via D?tz intramolecular benzannulation
Sen, Subhabrata,Kulkarni, Parag,Borate, Kailaskumar,Pai, Nandini R.
scheme or table, p. 4128 - 4131 (2009/12/01)
Novel fused heterocycles 1,10-dioxa-cyclopenta[a]fluorene and benzo[b]naphtho[2, 1-d]furans were synthesized via D?tz intramolecular benzannulation of alkyne tethered aryloxy chromium Fischer carbenes.
Novel PdII-mediated cascade carboxylative annulation to construct benzo[b]furan-3-carboxylic acids
Liao, Yun,Smith, Jennifer,Fathi, Reza,Yang, Zhen
, p. 2707 - 2709 (2007/10/03)
(Chemical Equation Presented) Benzo[b]furan-3-carboxylic acid (2) was generated from 1 by forming three new bonds in one step via a Pd II-mediated cascade carboxylative annulation. The proposed mechanism was supported by the observation of an u
Heterocycles by PtCl2-catalyzed intramolecular carboalkoxylation or carboamination of alkynes
Fuerstner, Alois,Davies, Paul W.
, p. 15024 - 15025 (2007/10/03)
PtCl2 constitutes a convenient catalyst for intramolecular hydroalkoxylation, carboalkoxylation, hydroamination, and carboamination reactions of alkynes, effecting the formation of substituted benzo[b]furan, indole-, and isochromene-1-one derivatives, respectively. This procedure allows for the transfer of (substituted) allyl, methoxymethyl (MOM), benzyloxymethyl (BOM), and (trimethylsilyl)ethoxymethyl (SEM) groups from oxygen to carbon and is compatible with functional groups that are susceptible to oxidative insertion of low valent metal species previously used for similar purposes. Although some of the reactions can even be carried out in air, the rates are significantly increased when conducted under an atmosphere of CO. A mechanistic rationale is proposed, implying activation of the alkyne by the carbophilic Pt(2+) template as the primary step of the catalytic cycle. Copyright
Palladium-catalyzed cyclization of o-alkynylphenols with allyl carbonates. A regioselective synthesis of 2-substituted-3-allylbenzo[b]furans
Cacchi, Sandro,Fabrizi, Giancarlo,Moro, Leonardo
, p. 741 - 745 (2007/10/03)
2-Substituted-3-allylbenzo[b]furans 3 can be prepared from o-alkynylphenols 1 and allyl carbonates 2 through a palladium-catalyzed O-allylation/cyclization sequence. Two basic procedures have been developed: a stepwise method based on the isolation of O-allyl derivatives 4 and their subsequent cyclization to 3 (procedure A) and a one-pot reaction omitting the isolation of 4 (procedure B). The cyclization of 4 in the presence of the electron-rich sterically-encumbered ligand tris(2,4,6-trimethoxyphenyl)phosphine (ttmpp) exhibits remarkable regioselectivity in that 3-allylbenzofurans in which the benzofuryl unit is bound to the less substituted allyl terminus are formed almost exclusively. Some loss of the stereochemistry of the carbon-carbon double bond is observed.
