Acid- mediated reactions under microfluidic conditions: A new strategy for practical synthesis of biofunctional natural products

• Katsunori Tanaka and
• Koichi Fukase

Beilstein J. Org. Chem. 2009, 5, No. 40, doi:10.3762/bjoc.5.40

• reactive sialyl donors having C-5 cyclic imides (Table 1), especially N-phthalimide 1a, by virtue of the “fixed-dipole moment effects” (α-only, 92% on 50 mg scale) [41]. The scale-up in a batch process, however, significantly decreased the yield and selectivity. Thus, a 100 mg scale reaction of 1a gave

• alternative to the N-phthalyl function, we also employed the C-5 azide group in sialyl donor 1b because this azide group should direct similar “fixed-dipole moment effects”, but should be easier to convert to naturally occurring N-substituents of neuraminic acids, i.e., N-acetyl or N-glycolyl groups (see

Convenient method for preparing benzyl ethers and esters using 2-benzyloxypyridine

• Susana S. Lopez and
• Gregory B. Dudley

Beilstein J. Org. Chem. 2008, 4, No. 44, doi:10.3762/bjoc.4.44

• trifluorotoluene, but toluene has a lower dipole moment and also is subject to Friedel–Crafts benzylation under the reaction conditions [6][22]. Trifluorotoluene (also known as benzotrifluoride or BTF) is recommended as a “green” solvent alternative to dichloromethane [23]. Benzylation reactions of N-Boc-serine 3d

The vicinal difluoro motif: The synthesis and conformation of erythro- and threo- diastereoisomers of 1,2-difluorodiphenylethanes, 2,3-difluorosuccinic acids and their derivatives

• David O'Hagan,
• Henry S. Rzepa,
• Martin Schüler and
• Alexandra M. Z. Slawin

Beilstein J. Org. Chem. 2006, 2, No. 19, doi:10.1186/1860-5397-2-19

• free energy differences arising from vibrational terms) does not alter the relative energies of a and b, despite a having a zero dipole moment and b having a relatively large value (3.5D) [26]. Although the more polar b should perhaps gain more from electrostatic solvation, it has a smaller solvent

• and appears to be dominated by solvation of the trans relationship of the aryl rings and the zero dipole moment, although the smaller 3JHH coupling of 2.6 Hz and the slightly larger 3JHF coupling of 15 Hz in the NMR, measurement does suggest some contribution of conformer b in solution. The threo-13

• significantly smaller than the NMR estimate and may reflect a limitation of the solvation model. Taking all of the data together (theory, X-ray and NMR) conformer d appears to be the most favoured conformer for threo-13 with both the fluorine and the phenyl rings gauche, despite its larger dipole moment. 2,3