Enantioselective total synthesis of putative dihydrorosefuran, a monoterpene with an unique 2,5-dihydrofuran structure

• Irene Torres-García,
• Josefa L. López-Martínez,
• Rocío López-Domene,
• Manuel Muñoz-Dorado,
• Ignacio Rodríguez-García and
• Miriam Álvarez-Corral

Beilstein J. Org. Chem. 2022, 18, 1264–1269, doi:10.3762/bjoc.18.132

• . Keywords: Ag(I) cyclization; allenylation; CpTiCl2; 2,5-dihydrofurans; monoterpenes; Introduction Artemisia pallens is an aromatic plant from southern India whose essential oil, known as Davana oil, has shown increasing interest mainly for its use in some beverages, cakes, pastries, etc., as well as in

Advances in mercury(II)-salt-mediated cyclization reactions of unsaturated bonds

• Sumana Mandal,
• Raju D. Chaudhari and
• Goutam Biswas

Beilstein J. Org. Chem. 2021, 17, 2348–2376, doi:10.3762/bjoc.17.153

• Hg(OTf)2-catalyzed conditions at lower temperature (Scheme 56) [117]. Following a similar strategy, mercury chlorate (Hg(ClO4)2) had been employed successfully as a cheap alternative to precious metals salts in the cyclization of α-allenol derivatives 185 to differently substituted 2,5-dihydrofurans

Rh(II)-mediated domino [4 + 1]-annulation of α-cyanothioacetamides using diazoesters: A new entry for the synthesis of multisubstituted thiophenes

• Jury J. Medvedev,
• Ilya V. Efimov,
• Yuri M. Shafran,
• Vitaliy V. Suslonov,
• Vasiliy A. Bakulev and
• Valerij A. Nikolaev

Beilstein J. Org. Chem. 2017, 13, 2569–2576, doi:10.3762/bjoc.13.253

• examples of such reactions are for instance syntheses of multisubstituted indolines [23][24][25], pyrrolidines [26][27][28][29], dihydropyrroles [29], tetrahydrofurans [27][28], and 2,5-dihydrofurans [31][32], which proceed as intramolecular interaction of generated ammonium or oxonium ylides with carbonyl

An approach towards azafuranomycin analogs by gold-catalyzed cycloisomerization of allenes: synthesis of (αS,2R)-(2,5-dihydro-1H-pyrrol-2-yl)glycine

• Jörg Erdsack and
• Norbert Krause

Beilstein J. Org. Chem. 2013, 9, 1936–1942, doi:10.3762/bjoc.9.229

• opens an efficient stereoselective access to chiral 2,5-dihydrofurans by axis-to-center chirality transfer (Scheme 1) [21][22][23][24][25][26][27][28][29][30][31][32] and was applied to the total synthesis of various natural products [29][30][31][32][33][34][35][36][37]. Likewise, the corresponding gold

Recent advances in the gold-catalyzed additions to C–C multiple bonds

• He Huang,
• Yu Zhou and
• Hong Liu

Beilstein J. Org. Chem. 2011, 7, 897–936, doi:10.3762/bjoc.7.103

• 1 can be selectively transformed into 2-alkyl- and 2-aryl-3-ethoxycarbonyl-2,5-dihydrofurans 2 by Ph3PAuCl and AgOTf through intramolecular hydroalkoxylation via a 5-endo mode [18]. Gold(III) chloride in catalytic amounts activates 3,4,6-tri-O-acetyl-D-glucal, 3,4,6-tri-O-acetyl-D-galactal, and 3,4

• strategy to construct furan analogues. Du et al. reported a highly efficient Au-catalyzed cyclization of (Z)-enynols that proceeded under mild reaction conditions. This methodology provided rapid access to substituted furans 6 and stereo-defined (Z)-5-ylidene-2,5-dihydrofurans 7 in a regioselective manner

• the gold-catalyzed cycloisomerization of α-hydroxyallenes 16 to 2,5-dihydrofurans 17 (Scheme 3) [25]. The best system was found to be AuBr3 in [BMIM][PF6]. The cycloisomerization of various alkyl- or arylsubstituted α-hydroxyallenes gave corresponding 2,5-dihydrofuran with complete axis-to-center

Gold-catalyzed heterocyclizations in alkynyl- and allenyl-β-lactams

• Benito Alcaide and
• Pedro Almendros

Beilstein J. Org. Chem. 2011, 7, 622–630, doi:10.3762/bjoc.7.73

• benzoate and TBS-protective groups under the gold-catalyzed conditions had been demonstrated, it was decided to see if (methoxymethyl)oxy substitution has a beneficial impact on the cyclization reactions. In the event, when γ-allenols 12 were treated with AuCl3 the 2,5-dihydrofurans 13 were the sole

Light-induced olefin metathesis

• Yuval Vidavsky and
• N. Gabriel Lemcoff

Beilstein J. Org. Chem. 2010, 6, 1106–1119, doi:10.3762/bjoc.6.127

• described in 1998 by Dixneuf et al. [65], who used the cationic allenylidene ruthenium complex 14 (Scheme 4) for the ene-yne RCM of propargylic allyl ethers into 3-vinyl-2,5-dihydrofurans. The best conditions reported for this reaction were the irradiation of a toluene solution of 14 and substrate with an