Zinc–gold cooperative catalysis for the direct alkynylation of benzofurans

• Yifan Li and
• Jérôme Waser

Beilstein J. Org. Chem. 2013, 9, 1763–1767, doi:10.3762/bjoc.9.204

• auration and reductive elimination [33]. The role of the zinc Lewis acid is not completely clear at this stage, but it may act by complexing the carboxylate group of the hypervalent iodine reagent, enhancing its electrophilic reactivity [19][34]. In fact, a complete shift of the 1H NMR signals of TIPS-EBX

• acid, together with the use of the hypervalent iodine reagent TIPS-EBX (8). Preliminary results obtained with 8-methoxypsoralen (2) demonstrated that the reaction could also be applied to more complex furocoumarin natural products. Experimental General procedure for the alkynylation of benzofurans

• Yifan Li Jerome Waser Laboratory of Catalysis and Organic Synthesis, Ecole Polytechnique Fédérale de Lausanne, EPFL SB ISIC LCSO, BCH4306, 1015 Lausanne, Switzerland 10.3762/bjoc.9.204 Abstract The direct alkynylation of benzofurans was achieved for the first time using the hypervalent iodine

The crystal structure of the Dess–Martin periodinane

• Albert Schröckeneder,
• Desiree Stichnoth,
• Peter Mayer and
• Dirk Trauner

Beilstein J. Org. Chem. 2012, 8, 1523–1527, doi:10.3762/bjoc.8.172

• the Dess–Martin periodinane (DMP), a hypervalent iodine reagent popular amongst synthetic chemists. In the solid state, the highly crystalline compound forms an intricate coordination polymer held together by intermolecular halogen and hydrogen bonds. Keywords: crystal structure; Dess–Martin

Approaches to α-amino acids via rearrangement to electron-deficient nitrogen: Beckmann and Hofmann rearrangements of appropriate carboxyl-protected substrates

• Sosale Chandrasekhar and
• V. Mohana Rao

Beilstein J. Org. Chem. 2012, 8, 1393–1399, doi:10.3762/bjoc.8.161

• , were thus formed in excellent yields (Table 3). The Hofmann rearrangement of carboxamides 9 was accomplished with one molar equivalent of phenyliodoso acetate [PhI(OAc)2] at 5–10 °C in methanolic KOH. The choice of the hypervalent iodine reagent was largely dictated by precedence [21][22][23]. The

Aryl nitrile oxide cycloaddition reactions in the presence of pinacol boronic acid ester

• Sarah L. Harding,
• Sebastian M. Marcuccio and
• G. Paul Savage

Beilstein J. Org. Chem. 2012, 8, 606–612, doi:10.3762/bjoc.8.67

• ; however, with the boronate ester benzonitrile oxide 5 only the anti cycloadduct was isolated and no syn cycloadduct was detected. Conclusion Aryl nitrile oxides can be prepared oxidatively in the presence of boronate esters by using the hypervalent iodine reagent, diacetoxyiodobenzene. Nitrile oxides

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

• . A gold-catalyzed direct alkynylation of indole and pyrrole heterocycles 204 with a benziodoxolone-based hypervalent iodine reagent 203 has been developed [91]. The functional group tolerance was greatly increased when compared with direct alkynylation of indoles reported previously. Kar et al