Synthetic avenues towards a tetrasaccharide related to Streptococcus pneumonia of serotype 6A

• Aritra Chaudhury,
• Mana Mohan Mukherjee and
• Rina Ghosh

Beilstein J. Org. Chem. 2018, 14, 1095–1102, doi:10.3762/bjoc.14.95

• orthogonal strategy for a one-pot synthesis of the targeted tetrasaccharide (Scheme 5). The disaccharide acceptor 4 was glycosylated with galactosyl trichloroacetimidate donor 2 at −15 °C using 30 mol % of TMSOTf. After full consumption of the starting materials (TLC), into the same pot the second acceptor 7

Orthogonal dual thiol–chloroacetyl and thiol–ene couplings for the sequential one-pot assembly of heteroglycoclusters

• Michele Fiore,
• Gour Chand Daskhan,
• Baptiste Thomas and
• Olivier Renaudet

Beilstein J. Org. Chem. 2014, 10, 1557–1563, doi:10.3762/bjoc.10.160

• Abstract We describe the first one-pot orthogonal strategy to prepare well-defined cyclopeptide-based heteroglycoclusters (hGCs) from glycosyl thiols. Both thiol–chloroactetyl coupling (TCC) and thiol–ene coupling (TEC) have been used to decorate cyclopeptides regioselectively with diverse combination of

• sugars. We demonstrate that the reaction sequence starting with TCC can be performed one-pot whereas the reverse sequence requires a purification step after the TEC reaction. The versatility of this orthogonal strategy has been demonstrated through the synthesis of diverse hGCs displaying alternating

Automated solid-phase peptide synthesis to obtain therapeutic peptides

• Veronika Mäde,
• Sylvia Els-Heindl and
• Annette G. Beck-Sickinger

Beilstein J. Org. Chem. 2014, 10, 1197–1212, doi:10.3762/bjoc.10.118

• and in some cases, the repetitive TFA acidolysis for Boc deprotection could have an impact on sensitive peptide bonds and acid-catalyzed side reactions [39]. And, since it is no orthogonal strategy, the Bn removal always leads to Boc deprotection. A tremendous diversity of side-chain protection groups

2-Allylphenyl glycosides as complementary building blocks for oligosaccharide and glycoconjugate synthesis

• Hemali D. Premathilake and
• Alexei V. Demchenko

Beilstein J. Org. Chem. 2012, 8, 597–605, doi:10.3762/bjoc.8.66

• efficient oligosaccharide assembly. Keywords: carbohydrates; glycosylation; leaving group; oligosaccharides; orthogonal strategy; selective activation; Introduction Current knowledge about the key roles of carbohydrates is still limited. However, thanks to the explosive growth of the field of glycobiology

• the nature of the protecting groups [8], and Ogawa’s orthogonal strategy is conceptually the most attractive approach that has been developed to date [9][10][11][12]. This technique implies the use of two orthogonal leaving groups, LGa and LGb, the selective activation of which can be reiterated to

• give streamlined access to oligosaccharides (Scheme 1). Yet, the orthogonal strategy remains underdeveloped, with too few examples to become universally applicable. Only Ogawa’s S-phenyl (SPh) versus fluoride [9][10][13] and our thioimidate-based approaches [14][15][16] are known. A very promising