Kinetics and mechanism of vanadium catalysed asymmetric cyanohydrin synthesis in propylene carbonate

• Michael North and
• Marta Omedes-Pujol

Beilstein J. Org. Chem. 2010, 6, 1043–1055, doi:10.3762/bjoc.6.119

• Lewis base catalysis is dominant; and b) when Lewis acid catalysis is dominant. Hammett correlations with catalyst 2 at 0 °C. Data in red are obtained in dichloromethane [52], whilst data in blue are obtained in propylene carbonate. Synthesis and transformation of nonracemic silyl-protected cyanohydrins

Preparation of aminoethyl glycosides for glycoconjugation

• Robert Šardzík,
• Gavin T. Noble,
• Martin J. Weissenborn,
• Andrew Martin,
• Simon J. Webb and
• Sabine L. Flitsch

Beilstein J. Org. Chem. 2010, 6, 699–703, doi:10.3762/bjoc.6.81

• 2-chloroethanol under acid catalysis, followed by peracetylation, nucleophilic substitution with azide and finally, reduction of the azido group [13][14]. Alternatively, the carbohydrate was first activated as the trichloroacetimidate or bromide followed by glycosylation with N-Cbz-aminoethanol [15

Chemical synthesis using enzymatically generated building units for construction of the human milk pentasaccharides sialyllacto-N-tetraose and sialyllacto-N-neotetraose epimer

• Dirk Schmidt and
• Joachim Thiem

Beilstein J. Org. Chem. 2010, 6, No. 18, doi:10.3762/bjoc.6.18

• ′-benzylidene-protected derivative 11 in almost quantitative yield by transacetalization with benzaldehyde dimethylacetal in acetonitrile under p-toluenesulfonic acid catalysis. Subsequent peracetylation with acetic anhydride/pyridine, selective cleavage of the benzylidene group with 80% acetic acid at 90 °C

A review of new developments in the Friedel–Crafts alkylation – From green chemistry to asymmetric catalysis

• Magnus Rueping and
• Boris J. Nachtsheim

Beilstein J. Org. Chem. 2010, 6, No. 6, doi:10.3762/bjoc.6.6

• –Crafts alkylation; green chemistry; hydroalkylation; hydroarylation; Lewis-acid catalysis; propargyl alcohols; Introduction In 1887 Charles Friedel and James Mason Crafts isolated amylbenzene after the treatment of amyl chloride with AlCl3 in benzene (Scheme 1) [1]. This was not only one of the first

Regioselective alkynylation followed by Suzuki coupling of 2,4-dichloroquinoline: Synthesis of 2-alkynyl- 4-arylquinolines

• Ellanki A. Reddy,
• Aminul Islam,
• K. Mukkanti,
• Venkanna Bandameedi,
• Dipal R. Bhowmik and
• Manojit Pal

Beilstein J. Org. Chem. 2009, 5, No. 32, doi:10.3762/bjoc.5.32

• ) 10.3762/bjoc.5.32 Abstract A two step synthesis of 2-alkynyl-4-arylquinolines has been accomplished via Pd/C-mediated regioselective C-2 alkynylation of 2,4-dichloroquinoline in water followed by Suzuki coupling at C-4 of the resulting 4-chloro derivative. Keywords: alkyne; boronic acid; catalysis; 2,4

Controlling hazardous chemicals in microreactors: Synthesis with iodine azide

• Johan C. Brandt and
• Thomas Wirth

Beilstein J. Org. Chem. 2009, 5, No. 30, doi:10.3762/bjoc.5.30

• the substrate, lack of acid catalysis, or a combination of these reasons. Additionally, the substitution pattern of the substrates led to an unexpected outcome of the reaction. Experimental Synthesis of tetrabutylammonium azide: Procedure I [23]: Sodium azide (200 mmol, 13 g) was dissolved in water

Recent progress on the total synthesis of acetogenins from Annonaceae

• Nianguang Li,
• Zhihao Shi,
• Yuping Tang,
• Jianwei Chen and
• Xiang Li

Beilstein J. Org. Chem. 2008, 4, No. 48, doi:10.3762/bjoc.4.48

Radical cascades using enantioenriched 7-azabenzonorbornenes and their applications in synthesis

• David M. Hodgson and
• Leonard H. Winning

Beilstein J. Org. Chem. 2008, 4, No. 38, doi:10.3762/bjoc.4.38

• some degree of isomerisation to (aminomethyl)indenes 22 and 25 respectively were observed, as indicated by the appearance of vinylic CH resonances in the 1H NMR spectra (δ 6.8–6.0). This isomerisation is presumably the result of trace acid catalysis, with the process likely proceeding via protonation

Allylsilanes in the synthesis of three to seven membered rings: the silylcuprate strategy

• Asunción Barbero,
• Francisco J. Pulido and
• M. Carmen Sañudo

Beilstein J. Org. Chem. 2007, 3, No. 16, doi:10.1186/1860-5397-3-16

• under Lewis acid catalysis. [10] Thus, silicon assisted cyclization of oxoallylsilanes 3–8 in the presence of TiCl4 or EtAlCl2 results in the formation of 3-methylene-1-cyclopentanols 11–14 with a high degree of stereocontrol (Scheme 3). [7] The cis stereochemistry observed in 11 might indicate a