AuBr₃-catalyzed azidation of per-O-acetylated and per-O-benzoylated sugars

• Jayashree Rajput,
• Srinivas Hotha and
• Madhuri Vangala

Beilstein J. Org. Chem. 2018, 14, 682–687, doi:10.3762/bjoc.14.56

• -benzoylated disaccharides needed 2–3 h of heating at 55 °C. Keywords: acylated sugars; azidation; gold(III) bromide; N-glycoside; oxophilicity; Introduction The past few decades had seen the enrichment of transition metal complexes in various glycosylation strategies [1]. In particular, gold complexes with

• role played by the oxophilicity of gold [26] towards the glycosylation reactions. Generally, easily accessible per-O-acetylated and per-O-benzoylated sugars are not regarded as effective glycosyl donors in glycosylation reactions since they require harsh reaction conditions due to the deactivating

Olefin metathesis in air

• Lorenzo Piola,
• Fady Nahra and
• Steven P. Nolan

Beilstein J. Org. Chem. 2015, 11, 2038–2056, doi:10.3762/bjoc.11.221

• modern metathesis catalysts [27][28][29][30], these all showed poor tolerance towards air and water, because of their high oxophilicity [3][8][9][16][27]. To date, there are no examples of their use in the presence of air. To overcome the sensitivity problems exhibited by early transition-based catalysts

• , late transition metals, which do not exhibit high oxophilicity, appeared as the most promising candidates for reactions performed in air. Indeed in 1988, Grubbs and Novak reported that not only ruthenium was an interesting candidate for olefin metathesis, but also that reactions were successfully

Gold(I)-catalyzed enantioselective cycloaddition reactions

• Fernando López and
• José L. Mascareñas

Beilstein J. Org. Chem. 2013, 9, 2250–2264, doi:10.3762/bjoc.9.264

• carbophilicity, low oxophilicity and high oxidation potential between gold(I) and gold(III) have shown a unique potential to unveil novel types of chemoselective and stereoselective cycloadditions involving alkynes, allenes or alkenes [24][25][26]. A lot of interest has been directed to the development of these

Gold-catalyzed glycosidation for the synthesis of trisaccharides by applying the armed–disarmed strategy

• Abhijeet K. Kayastha and
• Srinivas Hotha

Beilstein J. Org. Chem. 2013, 9, 2147–2155, doi:10.3762/bjoc.9.252

• oxophilicity of gold salts were observed to be major impediments for the synthesis of oligosaccharides. In order to overcome this problem, a systematic investigation of various leaving groups that bear an alkynyl moiety was carried out. The aim was to find a better leaving group, which would facilitate the

Recent advances in direct C–H arylation: Methodology, selectivity and mechanism in oxazole series

• Cécile Verrier,
• Pierrik Lassalas,
• Laure Théveau,
• Guy Quéguiner,
• François Trécourt,
• Francis Marsais and
• Christophe Hoarau

Beilstein J. Org. Chem. 2011, 7, 1584–1601, doi:10.3762/bjoc.7.187

• the ring-close oxazole, a trend that is evidenced by 1H NMR spectroscopy and attributed to the strong covalent carbon–zinc bond along with the zinc’s low oxophilicity, and this thus allows subsequent palladium-catalyzed Negishi cross-coupling [31][32][33]. This first, highly efficient, stoichiometric

Gold(I)-catalyzed synthesis of γ-vinylbutyrolactones by intramolecular oxaallylic alkylation with alcohols

• Michel Chiarucci,
• Mirko Locritani,
• Gianpiero Cera and
• Marco Bandini

Beilstein J. Org. Chem. 2011, 7, 1198–1204, doi:10.3762/bjoc.7.139

• reasonably rationalized in terms of the high π-acidity and poor oxophilicity of the Au(I) species [37]. With the optimal catalytic systems in hand (IMesAuOTf or [dppf(AuNTf2)2], DCE, 80 °C), we verified the generality of the method by subjecting a range of malonyl alcohols 1b–j to the gold-catalyzed