Oxidative allylic rearrangement of cycloalkenols: Formal total synthesis of enantiomerically pure trisporic acid B

• Silke Dubberke,
• Muhammad Abbas and
• Bernhard Westermann

Beilstein J. Org. Chem. 2011, 7, 421–425, doi:10.3762/bjoc.7.54

• was filtered and evaporated to dryness. After the addition of a catalytic amount of hydroquinone the dark brown residue was heated at 180 °C for 1 h and then purified by distillation under reduced pressure to give (±)-1c (1.70 g, 40%). The kinetic resolution was carried out as follows: To phosphate

• presence of a catalytic amount of hydroquinone. The resulting suspension was heated under reflux in an argon atmosphere for 7 h. At the end of the reaction, ethyl acetate (1 mL) was added and the product separated from the chromium salts by passage through a short column of silica gel (petroleum/ethyl

Aromatic and heterocyclic perfluoroalkyl sulfides. Methods of preparation

• Vladimir N. Boiko

Beilstein J. Org. Chem. 2010, 6, 880–921, doi:10.3762/bjoc.6.88

• chlorides react with electron rich aromatic and heterocyclic compounds, to give SRF derivatives. Thus, phenol, o-hydroquinone and their derivatives react with CF3SCl to yield p-hydroxyaryl trifluoromethyl sulfides (Scheme 6). The best yields are achieved when electron-donating substituents are present on

• for the introduction of three CF3S-groups. This can be achieved either by activation with iron powder under pressure (or by conduction the reaction in a steel autoclave) or by the presence of two donor groups in meta-positions [71]. For p-hydroquinone, reaction with CF3SCl in the presence of pyridine

• CF3SH in the presence of pyridine to the bis-compound gave 2,3,5-tris(SCF3)hydroquinone [72] which could be subsequently converted into tetrakis(SCF3)-1,4-hydroquinone (Scheme 8). Unlike p-hydroquinone, resorcinols and phloroglucinols perhaps surprisingly react with RFSCl [75] to generate

Shelf-stable electrophilic trifluoromethylating reagents: A brief historical perspective

• Norio Shibata,
• Andrej Matsnev and
• Dominique Cahard

Beilstein J. Org. Chem. 2010, 6, No. 65, doi:10.3762/bjoc.6.65

• reagent 24 led to a mixture of 2-trifluoromethylaniline and 4-trifluoromethylaniline in a 4:1 ratio. p-Hydroquinone was trifluoromethylated with 23 to produce 2-trifluoromethyl-p-hydroquinone in 85% yield, whereas 2-trifluoromethylpyrrole was obtained from pyrrole in 87% yield with the same

Mitomycins syntheses: a recent update

• Jean-Christophe Andrez

Beilstein J. Org. Chem. 2009, 5, No. 33, doi:10.3762/bjoc.5.33

• possessing a hydroquinone (protected or not) in place of the original quinone are identified by inclusion of the prefix leuco in reference to the Greek word leukos (clear, white) and the lack of intense color usually specific of the corresponding quinone ring. The mitomycins A and C differ only by the

• -electron reduction to give the semiquinone [41][42][43][44] or by a two-electron reduction to give the hydroquinone [45][46][47]. Studies have shown that one-electron reduction in an organic solvent can trigger formation of the semiquinone and the subsequent reaction cascade [42]. On the other hand, two

• -electron reduction led to formation of the stable hydroquinone, which can be oxidized back to the quinone in the presence of oxygen [48]. Nonetheless, different results were observed in water where both one- and two-electron reductions gave the same DNA adducts. Moreover, the disproportion of the

N-1 regioselective Michael- type addition of 5-substituted uracils to (2-hydroxyethyl) acrylate

• Sławomir Boncel,
• Dominika Osyda and
• Krzysztof Z. Walczak

Beilstein J. Org. Chem. 2007, 3, No. 40, doi:10.1186/1860-5397-3-40

• MeCN (Table 1, footnote). The avoidance of polymerization of acrylic substrates was achieved by portion-wise addition to the reaction mixture. Moreover, addition of polymerization inhibitors, explicitly hydroquinone, did not cause any significant changes in polymerization rate. The optimum reaction