Benzylidene Acetal Protecting Group as Carboxylic Acid Surrogate: Synthesis of Functionalized Uronic Acids and Sugar Amino Acids

Banerjee, Amit; Senthilkumar, Soundararasu; Baskaran, Sundarababu

doi:10.1002/chem.201503998

Cited by 15 publications

(13 citation statements)

References 71 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The 91% yield included 72% of the product isolated by crystallisation and 19% by chromatography of the mother liquor. In the case of 2aa, the yield (87%) and reaction rate (7.7 h) are much better than those of classic methods catalysed by ZnCl 2 (52-72% yields, 3-36 h) 11,12,23,24 or TsOH (77% yield, 170 h). 25 There have been some improvements using various reagents such as TMSOTf, 26 Sc(NTf 2 ) 3 , 27 Bi(OTf) 3 28 and NBS.…”

Section: Resultsmentioning

confidence: 89%

From organocatalysed desilylations to high-yielding benzylidenations of electron-deficient benzaldehydes

Niu

Xing

2017

Journal of Chemical Research

View full text Add to dashboard Cite

A new type of organoprecatalyst (MeSCH2Cl/KI) for desilylation and benzylidenation reactions has been designed. Both reactions are user friendly and high yielding (71–>99%) and have fast reaction rates. The desilylation of iodo silyl ethers was achieved with no sequential etherification side reactions like those seen for reactions when using TBAF. In the application of the catalytic system to a 6-TBDMS ether of a glucoside, glucoside benzylidenations using electron-deficient benzaldehydes were achieved in 87% yield compared with the previously reported yields of 69–77%. Altogether, 14 benzylidenation reactions were realised using silyloxy alcohols and electron-deficient benzaldehydes instead of their activated acetal forms. In terms of reaction rates and yields, the order of the benzylidenations is p-fluorobenzaldehyde > benzaldehyde > p-anisaldehyde, and a possible mechanism is discussed. These experiments have preliminarily differentiated this cost-effective catalytic system from the classic Lewis acids.

show abstract

Section: Resultsmentioning

confidence: 89%

From organocatalysed desilylations to high-yielding benzylidenations of electron-deficient benzaldehydes

Niu

Xing

2017

Journal of Chemical Research

View full text Add to dashboard Cite

show abstract

“…Sugar amino acids and their assembled oligomers, known as carbopeptoids, are commonly studied as foldamers to discover the structural consequences 16 – 36 . Accordingly, glycosaminuronic acid analogues 3′ and 4′ served as versatile scaffolds in construction of di-, tetra- and octamers.…”

Section: Resultsmentioning

confidence: 99%

“…Sugar amino acids, as carbohydrate derivatives bearing both amino and carboxylic acid functional groups, represent an important class of multifunctional building blocks for discovering new drugs and materials 1 – 15 . A plenty diversity of SAAs have been designed and synthesized by many research groups in the past decades, because they are amenable to serve as glycomimetics or peptidomimetics with well-defined structures and distinct biological properties 16 – 36 . Glucosaminuronic acid 1 and galactosaminuronic acid 2 (Fig.…”

Section: Introductionmentioning

confidence: 99%

Synthesis and conformational analysis of linear homo- and heterooligomers from novel 2-C-branched sugar amino acids (SAAs)

Tian

Zhang

et al. 2018

Sci Rep

View full text Add to dashboard Cite

Sugar amino acids (SAAs), as biologically interesting structures bearing both amino and carboxylic acid functional groups represent an important class of multifunctional building blocks. In this study, we develop an easy access to novel SAAs in only three steps starting from nitro compounds in high yields in analytically pure form, easily available by ceric (IV) mediated radical additions. Such novel SAAs have been applied in the assembly of total nine carbopeptoids with the form of linear homo- and heterooligomers for the structural investigations employing circular dichroism (CD) spectroscopy, which suggest that the carbopeptoids emerge a well-extended, left (or right)-handed conformation similar to polyproline II (PPII) helices. NMR studies also clearly demonstrated the presence of ordered secondary structural elements. 2D-ROESY spectra were acquired to identify i+1NH ↔ iC1H, iC2H correlations which support the conformational analysis of tetramers by CD spectroscopy. These findings provide interesting information of SAAs and their oligomers as potential scaffolds for discovering new drugs and materials.

show abstract

“…In 2016, the lab of Baskaran at IIT‐Madras published a method that uses the well‐known RuCl 3 ‐NaIO 4 system to achieve a one‐pot conversion of benzylidene protected furanoses ( 50 ) into benzoyl protected uronic acids (Table ) …”

Section: Furansmentioning

confidence: 99%

“…Similar to the furanoses, the one‐pot transformation of benzylidene‐protected pyranoses to the corresponding 4‐ O ‐benzoyl uronic acids was established by oxidation with RuCl 3 ‐NaIO 4 (Scheme ) . The method was found to be compatible with several functional groups, including esters ( 159 ), silyl ethers ( 248 ), tosylates, phthalimides and azides.…”

Section: Pyransmentioning

confidence: 99%

Regioselective Ring Opening of 1,3‐Dioxane‐Type Acetals in Carbohydrates

et al. 2018

View full text Add to dashboard Cite

The (regio)selective manipulation of hydroxyl groups in carbohydrates has been a long‐standing challenge in (bio)organic chemistry and continues to trigger the creative minds of many chemists. Among the various strategies that have been developed to address these issues, mostly relying on multistep procedures involving the use of protecting groups, the regioselective ring opening of 1,3‐dioxane‐type acetals has emerged as a powerful tool. Since the first papers on this subject appeared in the 1960s, a large variety in both acetal types and reagents for their partial cleavage has come to the fore. This review aims to give an overview of the different carbohydrate‐derived ring systems, ranging from four‐ to seven‐membered rings, on which regioselective ring‐openings have been performed, along with the appropriate reagents and combinations thereof. The transformations on 1,3‐dioxane acetals fit in a larger group of ring opening reactions of structurally related cyclic functional groups, including 1,3‐dioxolanes, 1,3‐oxathianes, orthoesters, cyclic carbonates and silylene acetals, which will not be discussed in this review.

show abstract

Benzylidene Acetal Protecting Group as Carboxylic Acid Surrogate: Synthesis of Functionalized Uronic Acids and Sugar Amino Acids

Cited by 15 publications

References 71 publications

From organocatalysed desilylations to high-yielding benzylidenations of electron-deficient benzaldehydes

From organocatalysed desilylations to high-yielding benzylidenations of electron-deficient benzaldehydes

Synthesis and conformational analysis of linear homo- and heterooligomers from novel 2-C-branched sugar amino acids (SAAs)

Regioselective Ring Opening of 1,3‐Dioxane‐Type Acetals in Carbohydrates

Contact Info

Product

Resources

About