Chemical and chemoenzymatic routes to bridged homoarabinofuranosylpyrimidines: Bicyclic AZT analogues

• Sandeep Kumar,
• Jyotirmoy Maity,
• Banty Kumar,
• Sumit Kumar and
• Ashok K. Prasad

Beilstein J. Org. Chem. 2022, 18, 95–101, doi:10.3762/bjoc.18.10

• regioselective protection of the primary hydroxy group of diol 17 using TBDPS-Cl in pyridine at room temperature afforded TBDPS-protected furanoside 18, which on acetolysis using AcOH/Ac2O/H2SO4 (100:10:0.1) afforded the anomeric mixture of coupling sugar 19a,b in 80% yield. The Vorbrüggen coupling [29] of

A semisynthesis of 3'-O-ethyl-5,6-dihydrospinosyn J based on the spinosyn A aglycone

• Kai Zhang,
• Shenglan Liu,
• Anjun Liu,
• Hongxin Chai,
• Jiarong Li and
• Lamusi A

Beilstein J. Org. Chem. 2017, 13, 2603–2609, doi:10.3762/bjoc.13.257

• ). Rhamnose contains several hydroxy groups with similar chemical activities, so regioselective protection and alkylation are challenges. Common protecting groups of the hydroxy group at 1-position of rhamnose include allyl [28], methoxyphenyl [29] and 1-thiorhamnoside [30]. Compared with the reaction

An efficient synthesis of a C₁₂-higher sugar aminoalditol

• Łukasz Szyszka,
• Anna Osuch-Kwiatkowska,
• Mykhaylo A. Potopnyk and
• Sławomir Jarosz

Beilstein J. Org. Chem. 2017, 13, 2146–2152, doi:10.3762/bjoc.13.213

• , including cyclic ones. We decided to perform a model study on the efficient differentiation of the terminal positions in such higher sugars or alditols, which could open a route to complex polyhydroxylated derivatives. Results and Discussion A regioselective protection of one of the primary hydroxy groups

Synthesis of D-manno-heptulose via a cascade aldol/hemiketalization reaction

• Yan Chen,
• Xiaoman Wang,
• Junchang Wang and
• You Yang

Beilstein J. Org. Chem. 2017, 13, 795–799, doi:10.3762/bjoc.13.79

• bis(tributyltin) oxide and subsequent exposure to p-methoxybenzyl (PMB) chloride in the presence of tetra-n-butylammonium bromide (TBAB) at 110 °C led to regioselective protection of the 3-OH with the PMB group, affording the 3-O-PMB protected alcohol 7 (55%) [41]. At this stage, we initially planned

Orthogonal protection of saccharide polyols through solvent-free one-pot sequences based on regioselective silylations

• Serena Traboni,
• Emiliano Bedini and
• Alfonso Iadonisi

Beilstein J. Org. Chem. 2016, 12, 2748–2756, doi:10.3762/bjoc.12.271

• experimentally simple tool for the straightforward access to saccharide building-blocks useful in organic synthesis. Keywords: carbohydrates; one-pot synthesis; regioselective protection; silyl protecting group; solvent-free reaction; Introduction The application of an orthogonal set of protecting groups

• activation effect of boron complexes [33]. Over the last years, we have addressed our interest towards the development of solvent-free protocols aimed at regioselective protection of highly functionalized saccharide substrates. This effort led to a simple protocol for the selective benzylation of primary

• compounds. Regioselective silylation of 1 under solvent free conditionsa. Regioselective silylation of saccharide primary alcohols under solvent-free conditionsa. Solvent-free regioselective silylations committing secondary alcoholsa. One-pot, regioselective protection of sugar polyols with silyl and alkyl

Useful access to enantiomerically pure protected inositols from carbohydrates: the aldohexos-5-uloses route

• Felicia D’Andrea,
• Giorgio Catelani,
• Lorenzo Guazzelli and
• Venerando Pistarà

Beilstein J. Org. Chem. 2016, 12, 2343–2350, doi:10.3762/bjoc.12.227

• findings have been reported so far [46][47], the regioselective protection of inositols is still a troublesome area due to the comparable reactivity of the secondary hydroxy functions. Therefore, the carbocyclization of a selectively protected dicarbonyl sugar, namely the L-lyxo derivative 20, whose

Total synthesis of the proposed structure of astakolactin

• Takayuki Tonoi,
• Keisuke Mameda,
• Moe Fujishiro,
• Yutaka Yoshinaga and
• Isamu Shiina

Beilstein J. Org. Chem. 2014, 10, 2421–2427, doi:10.3762/bjoc.10.252

• provided aldehyde 6. The aldol reaction of 6 with ester 7 in the presence of base and the subsequent oxidative deselenization of the resulting adduct 14 yielded a Morita–Baylis–Hillman-type product 5 [37] in two steps. Reduction of 5 and the regioselective protection of the less-hindered primary hydroxy

Synthesis of zearalenone-16-β,D-glucoside and zearalenone-16-sulfate: A tale of protecting resorcylic acid lactones for regiocontrolled conjugation

• Hannes Mikula,
• Julia Weber,
• Dennis Svatunek,
• Philipp Skrinjar,
• Gerhard Adam,
• Rudolf Krska,
• Christian Hametner and
• Johannes Fröhlich

Beilstein J. Org. Chem. 2014, 10, 1129–1134, doi:10.3762/bjoc.10.112

• investigations. Conclusion In summary, different methods for the regioselective protection of resorcylic acid esters and lactones were investigated for subsequent regiocontrolled glucosylation and sulfation. Whereas acetyl and p-methoxybenzyl protection led to undesired products, TIPS-protected RALs were

• -acetylzearalenone (14). (A) Regioselective p-methoxybenzylation of 9. (B) Synthesis of the ZEN-16-Glc mimic 17. Regioselective protection of ZEN (1) and failed PMB cleavage of the glucosylated intermediate 19. Synthesis of (A) ZEN mimic glucoside 17 and (B) ZEN-16-β,D-glucoside (7); a: TIPS-Cl, imidazole, 16 h, rt

• first chemical synthesis of the ZEN-derivative 14-O-acetylzearalenone (14-AcZEN, produced by some Fusarium strains) [28] is reported. Results and Discussion The general strategy for regiocontrolled conjugation at position 2’ of resorcylic acid esters and lactones is shown in Scheme 1. Regioselective

Synthesis of the B-seco limonoid core scaffold

• Hanna Bruss,
• Hannah Schuster,
• Rémi Martinez,
• Markus Kaiser,
• Andrey P. Antonchick and
• Herbert Waldmann

Beilstein J. Org. Chem. 2014, 10, 194–208, doi:10.3762/bjoc.10.15

• taxoid building block. Regioselective protection of the less hindered ketone in 80 and diastereoselective hydrogenation of the double bond could be achieved in a known one-pot procedure [54][55] affording the cis-hydrindanone and providing the desired stereochemistry at C4 and C5. Ozonolytic cleavage of

Synthesis and testing of the first azobenzene mannobioside as photoswitchable ligand for the bacterial lectin FimH

• Vijayanand Chandrasekaran,
• Katharina Kolbe,
• Femke Beiroth and
• Thisbe K. Lindhorst

Beilstein J. Org. Chem. 2013, 9, 223–233, doi:10.3762/bjoc.9.26

• mannoside 6 in a basically quantitative reaction. Then, a standard protecting-group strategy was employed to allow the synthesis of the 3-OH unprotected mannoside 10, which is a key intermediate serving as the glycosyl acceptor in the following disaccharide synthesis. First, regioselective protection of the

An efficient partial synthesis of 4′-O-methylquercetin via regioselective protection and alkylation of quercetin

• Nian-Guang Li,
• Zhi-Hao Shi,
• Yu-Ping Tang,
• Jian-Ping Yang and
• Jin-Ao Duan

Beilstein J. Org. Chem. 2009, 5, No. 60, doi:10.3762/bjoc.5.60

• selective protection of the catechol group with dichlorodiphenylmethane in diphenyl ether as solvent and on the selective protection of the hydroxyl groups at positions 3 and 7 with chloromethyl ether. Keywords: alkylation; high yield; 4′-O-methylquercetin; partial synthesis; regioselective protection

Solvent- controlled regioselective protection of allyl- 4,6-benzylidene glucopyranosides

• Kerry Ann Ness and
• Marie E. Migaud

Beilstein J. Org. Chem. 2007, 3, No. 26, doi:10.1186/1860-5397-3-26