Regioselective mono and multiple alkylation of diols and polyols catalyzed by organotin and its applications on the synthesis of value-added carbohydrate intermediates

Xu, Hengfu; Ren, Bo; Zhao, Wei; Xin, Xiaoting; Lu, Yuchao; Pei, Yuxin; Dong, Hai; Pei, Zhichao

doi:10.1016/j.tet.2016.04.076

Cited by 26 publications

(15 citation statements)

References 45 publications

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“…The synthesis efficiencies of 2-thio-, 4-thio-and 2,4-dithioglycosides are key to obtaining 2-deoxy-, 4-deoxy-and 2,4dideoxy-glycosides by desulfurization (Ren et al, 2015;Wu et al, 2015;Ge et al, 2017a,b;Norberg et al, 2017). We have developed several efficient methods to synthesize glycosides in which both 3-and 6-positions were protected (Ren et al, 2014b;Xu et al, 2016;Zhang et al, 2016;Lv et al, 2018aLv et al, ,b, 2019. One of the methods using acetate (Ren et al, 2014b) or benzoate (Zhang et al, 2016) as a catalyst is particularly convenient and environmentally friendly.…”

Section: Resultsmentioning

confidence: 99%

Improved Synthesis of Sulfur-Containing Glycosides by Suppressing Thioacetyl Migration

Luo

Zhang

et al. 2020

Front. Chem.

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Complex mixtures were often observed when we attempted to synthesize 4-thio-and 2,4-dithio-glycoside derivatives by double parallel and double serial inversion, thus leading to no or low yields of target products. The reason was later found to be that many unexpected side products were produced when a nucleophile substituted the leaving group on the substrate containing the thioacetate group. We hypothesized that thioacetyl migration is prone to occur due to the labile thioacetate group even under weak basic conditions caused by the nucleophile, leading to this result. Therefore, we managed to inhibit the generation of thiol groups from thioacetate groups by the addition of an appropriate amount of conjugate acid/anhydride, successfully improving the synthesis of 4-thio-and 2,4-dithio-glycoside derivatives. The target products which were previously difficult to synthesize, were herein obtained in relatively high yields. Finally, 4-deoxy-and 2,4-dideoxy-glycoside derivatives were efficiently synthesized through the removal of thioacetate groups under UV light, starting from 4-thio-and 2,4-dithio-glycoside derivatives.

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Section: Resultsmentioning

confidence: 99%

Improved Synthesis of Sulfur-Containing Glycosides by Suppressing Thioacetyl Migration

Luo

Zhang

et al. 2020

Front. Chem.

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“…Recently, several environmentally friendly methods have been developed to substitute the traditional organotin methods, including the use of oranoboron, organotin, and organoiron catalysts, all of which have their respective advantages and shortcomings. For example, alkylations for which K 2 CO 3 is used as a base require high reaction temperatures (70–90 °C; Scheme a) –. Temperature‐sensitive substrates may not tolerate these high‐temperature conditions.…”

Section: Methodsmentioning

confidence: 99%

“…On the basis of the mechanism studies of organotin‐mediated selective protections, we developed an organotin‐catalyzed alkylation method, for which the reaction was performed at 80 °C for 3 h. The proposed mechanism suggests that a dioxolane five‐ or six‐membered ring stannylene intermediate plays an important role in the catalysis process. Given that the stannylene intermediate is formed by coordination of two deprotonated hydroxy groups to a tin atom, strong basicity should favor the formation of this intermediate.…”

Section: Methodsmentioning

confidence: 99%

Highly Efficient Selective Benzylation of Carbohydrates Catalyzed by Iron(III) with Silver Oxide and Bromide Anion as Co‐catalysts

Ren

Tian

et al. 2017

ChemCatChem

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A highly efficient, green, and regioselective method for the benzylation of diols and polyols was developed. With the use of Ag2O (0.6 equiv.) and tetrabutylammonium bromide (0.1 equiv.) as co‐catalysts, the iron(III)‐catalyzed benzylation reaction proceeded to completion at 40 °C within 2–3 h and gave the products in high yields with high regioselectivities. A mechanism involving the principle of enhanced basicity of Ag2O by soft anions was proposed.

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“…It is pertinent to specify at this stage that some tin-catalyzed approaches in solution have appeared after the described report on the solvent-free conditions, with considerable simplification over the traditional stepwise stoichiometric method [48][49][50][51][52]. It is also worth observing that solvent-free benzylation protocols described herein have already been incorporated into a variety of synthetic projects [53][54][55][56], to testify their practical scope.…”

Section: Selective Modifications Based On Formation Of Ether Linkagesmentioning

confidence: 99%

Solvent-Free Approaches in Carbohydrate Synthetic Chemistry: Role of Catalysis in Reactivity and Selectivity

et al. 2020

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Owing to their abundance in biomass and availability at a low cost, carbohydrates are very useful precursors for products of interest in a broad range of scientific applications. For example, they can be either converted into basic chemicals or used as chiral precursors for the synthesis of potentially bioactive molecules, even including nonsaccharide targets; in addition, there is also a broad interest toward the potential of synthetic sugar-containing structures in the field of functional materials. Synthetic elaboration of carbohydrates, in both the selective modification of functional groups and the assembly of oligomeric structures, is not trivial and often entails experimentally demanding approaches practiced by specialized groups. Over the last years, a large number of solvent-free synthetic methods have appeared in the literature, often being endowed with several advantages such as greenness, experimental simplicity, and a larger scope than analogous reactions in solution. Most of these methods are catalytically promoted, and the catalyst often plays a key role in the selectivity associated with the process. This review aims to describe the significant recent contributions in the solvent-free synthetic chemistry of carbohydrates, devoting a special critical focus on both the mechanistic role of the catalysts employed and the differences evidenced so far with corresponding methods in solution.

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Regioselective mono and multiple alkylation of diols and polyols catalyzed by organotin and its applications on the synthesis of value-added carbohydrate intermediates

Cited by 26 publications

References 45 publications

Improved Synthesis of Sulfur-Containing Glycosides by Suppressing Thioacetyl Migration

Improved Synthesis of Sulfur-Containing Glycosides by Suppressing Thioacetyl Migration

Highly Efficient Selective Benzylation of Carbohydrates Catalyzed by Iron(III) with Silver Oxide and Bromide Anion as Co‐catalysts

Solvent-Free Approaches in Carbohydrate Synthetic Chemistry: Role of Catalysis in Reactivity and Selectivity

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