<i>C</i>‐Glycosyl Amino Acids through Hydroboration–Cross‐Coupling of <i>exo</i>‐Glycals and Their Application in Automated Solid‐Phase Synthesis

Koch, Stefan; Schollmeyer, Dieter; Löwe, Holger; Kunz, Horst

doi:10.1002/chem.201300150

Cited by 29 publications

(18 citation statements)

References 63 publications

(40 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…During these studies, 1 H NMR analysis of the olefination products 8 confirmed that an epimerization had, indeed, occurred in all cases. We were pleased to notice no self-condensation products corresponding to 5.…”

mentioning

confidence: 57%

“…

…”

mentioning

confidence: 99%

See 1 more Smart Citation

A Carbohydrate-Based Julia–Kocienski Reagent for Syntheses of Chain-Extended and C-Linked Saccharides

Bull

Kunz

2014

Synthesis

Self Cite

View full text Add to dashboard Cite

The carbohydrate-derived Julia-Kocienski reagent 2-{[(3aS,4S,6R,6aR)-6-methoxy-2,2-dimethyltetrahydrofuro [3,4-d] [1,3]dioxol-4-yl]methylsulfonyl}-1,3-benzothiazole (6) was prepared from D-ribose and investigated in the eponymous olefination. The base-promoted generation of the Julia anion induced a rearrangement to the corresponding L-lyxose epimer 2- 3-benzothiazole (12), which reacted readily with aldehydes and with a gluconolactone. The latter reaction furnished an exo-glycal-linked C-diglycoside.As part of ongoing investigations into new methodologies for the incorporation of C-linked carbohydrate units into saccharides and glycopeptides, 1 our attention turned to the Julia-Kocienski olefination 2 as a promising and underdeveloped tool in the synthesis of glycoconjugates and longchain carbohydrates. As carbohydrate units integrated into the backbone of larger structures are a common feature in natural products, they present themselves as important synthetic targets. 3 The Kocienski-Lythgoe modifications of the Julia olefination have already been used to great effect in the preparation of such compounds, however, to date research has focused on using the carbohydrate fragment as the carbonyl-containing substrate rather than the reagent itself. Furthermore, such protocols are most commonly applied to the preparation of simple exo-glycals from carbohydrate lactones. 4 These exo-glycals are typically the products of sterically undemanding electron-poor reagents and simple carbonyl methyleneations. 5 The Julia-Kocienski reaction has thereby demonstrated its synthetic compatibility with carbohydrate chemistry.With the hope of utilizing the innate advantages of this versatile methodology, we envisaged the benzothiazole-2-sulfone 6 as a promising candidate for effecting the coupling of a furanose with carbonyl compounds, being, to our knowledge, the first example of a carbohydrate-based Julia reagent. 6 However, the formation of stabilized anions on carbohydrate systems is known to be problematic due to the invariable presence of a leaving group in the β-position. In this case, however, the leaving anion is tethered through the ring system, offering production of the carbanion through conjugate re-addition and subsequent ring closure. A similar approach has been investigated by Secrist et al., who prepared the corresponding triphenylphosphosphonium salt 1 to use its ylide in the Wittig olefination. 7 The ylide reacted readily with aromatic and aliphatic aldehydes to form the chain-extended carbohydrate. Interestingly, in all cases the product had undergone a rearrangement to the L-lyxose epimer 2 via concomitant epimerization of the C4 position through the ring-opened β-elimination product 3 7 (Scheme 1). Furthermore, when the ylide was presented with various ketones it was observed to undergo a self-condensation reaction with the intermediate aldehyde 4 to afford the alkene-linked decafuranose derivative 5. The fact that the self-condensed product contains solely L-lyxose and that no self-condensation is observed w...

show abstract

mentioning

confidence: 57%

“…

…”

mentioning

confidence: 99%

A Carbohydrate-Based Julia–Kocienski Reagent for Syntheses of Chain-Extended and C-Linked Saccharides

Bull

Kunz

2014

Synthesis

Self Cite

View full text Add to dashboard Cite

show abstract

“…(4 S )‐4‐[ C ‐(4‐ O ‐Acetyl‐2,3,6‐tri‐ O ‐benzyl‐β‐ D ‐glucopyranosyl)]‐3‐(9 H ‐fluoren‐9‐ylmethoxycarbonyl)‐1,3‐oxazolidin‐5‐one [Fmoc‐C‐Tyr‐(β‐AcBn 3 Glc)‐oxazolidinone, 2d]: Fmoc‐C‐Tyr‐(β‐AcBn 3 Glc)‐OH ( 1d ;32 8.6 mg, 9.83 μmol) was dissolved in acetonitrile (1.00 mL). Paraformaldehyde (50 mg) and p ‐toluenesulfonic acid (3.20 mg, 18.6 μmol) were added and the mixture was stirred for 2 d at room temperature and 2 d at 40 °C.…”

Section: Methodsmentioning

confidence: 99%

Fluorenylmethoxycarbonyl‐Protected O‐Glycosyl‐N‐methyl Amino Acids: Building Blocks for the Synthesis of Conformationally Tuned Glycopeptide Antigens

2015

Self Cite

View full text Add to dashboard Cite

Peptide antibiotics often contain N‐methylated amino acids. These N‐methylamino components enhance the metabolic stability and strongly influence the conformational behavior of these peptide drugs. N‐Methyl‐O‐glycosyl amino acids, in particular, threonine and serine derivatives, are unknown so far. Fmoc‐protected N‐methyl‐O‐glycosyl‐threonine and ‐serine building blocks, including sialyl TN antigens, have been synthesized for the first time by converting the Fmoc‐protected O‐glycosyl amino acids or their tert‐butyl esters into the corresponding oxazolidinones followed by reductive ring‐opening. These new components are considered interesting for the construction of modified mucin glycopeptide anti‐tumor vaccines with extended biological half‐life.

show abstract

“…The synthetic utility of this methodology was demonstrated by a four-step one-pot synthesis and a successful recycling of the reaction medium [127]. B-alkyl SMC, in particular, was likewise applied in the synthesis of beneficial products [130][131][132]. Two examples are shown in Scheme 16: Cytochalasin Z 8 and Ieodomycin D, which belong to the family of secondary fungal metabolite with a wide range of biological activities that target cytoskeletal processes [133][134][135].…”

Section: B-alkyl Smcs Using Bbn Variants (9-meo-9-bbn and Obbd Derivamentioning

confidence: 99%

Recent Advances in Metal-Catalyzed Alkyl–Boron (C(sp3)–C(sp2)) Suzuki-Miyaura Cross-Couplings

El‐Maiss

Dine

et al. 2020

Catalysts

View full text Add to dashboard Cite

Boron chemistry has evolved to become one of the most diverse and applied fields in organic synthesis and catalysis. Various valuable reactions such as hydroborylations and Suzuki–Miyaura cross-couplings (SMCs) are now considered as indispensable methods in the synthetic toolbox of researchers in academia and industry. The development of novel sterically- and electronically-demanding C(sp3)–Boron reagents and their subsequent metal-catalyzed cross-couplings attracts strong attention and serves in turn to expedite the wheel of innovative applications of otherwise challenging organic adducts in different fields. This review describes the significant progress in the utilization of classical and novel C(sp3)–B reagents (9-BBN and 9-MeO-9-BBN, trifluoroboronates, alkylboranes, alkylboronic acids, MIDA, etc.) as coupling partners in challenging metal-catalyzed C(sp3)–C(sp2) cross-coupling reactions, such as B-alkyl SMCs after 2001.

show abstract

C‐Glycosyl Amino Acids through Hydroboration–Cross‐Coupling of exo‐Glycals and Their Application in Automated Solid‐Phase Synthesis

Cited by 29 publications

References 63 publications

A Carbohydrate-Based Julia–Kocienski Reagent for Syntheses of Chain-Extended and C-Linked Saccharides

A Carbohydrate-Based Julia–Kocienski Reagent for Syntheses of Chain-Extended and C-Linked Saccharides

Fluorenylmethoxycarbonyl‐Protected O‐Glycosyl‐N‐methyl Amino Acids: Building Blocks for the Synthesis of Conformationally Tuned Glycopeptide Antigens

Recent Advances in Metal-Catalyzed Alkyl–Boron (C(sp3)–C(sp2)) Suzuki-Miyaura Cross-Couplings

Contact Info

Product

Resources

About