- Stereoselective synthesis of D-galactal-derived N-ethoxycarbonyl aziridine, as a new, improved synthetic protocol to glycal-derived N-activated vinyl aziridines
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A new protocol for the synthesis of D-galactal-derived N-ethoxycarbonyl vinyl aziridine 1β-CO2Et, starting from tri-O-acetyl-D-glucal, is described. The new protocol constitutes a simple and fast access, with a satisfactory overall yield (5 steps, 36%), to a D-galactal-derived vinyl aziridine with a clear improvement compared with the previously described procedure leading to the structurally related N-nosyl aziridine 1β-Ns which, starting from the same precursor, proceeded through 13 steps with a low, decidedly unsatisfactory, overall yield (3%).
- Princiotto, Salvatore,Di Bussolo, Valeria,Bordoni, Vittorio,Favero, Lucilla,Crotti, Stefano,Uccello Barretta, Gloria,Balzano, Federica,Crotti, Paolo
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Read Online
- A Highly Efficient Magnetic Iron(III) Nanocatalyst for Ferrier Rearrangements
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A novel and highly efficient magnetic Fe 3 O 4 &at;C&at;Fe(III) core-shell catalyst, in which the carbon shell was prepared from lotus leaf, was fabricated. This nanocatalyst was successfully applied in the synthesis of a series of 2,3-unsaturated O- glycosides in excellent yields and with high selectivity, especially in the case of 2-halo O- glycosides, which differ in reactivity from nonsubstituted O- glycosides, but which have scarcely been explored before. Moreover, the catalyst could be easily separated from the reaction by the application of an external magnetic force and reused a minimum of five times without any significant decrease in the yields of the products. In addition, the reaction proceeded readily on a gram scale, which provides a bright prospect for future applications.
- Chen, Heshan,Ding, Zekun,Dong, Youxian,Guo, Hong,Jiang, Nan,Qiu, Saifeng,Xu, Xiaoxia,Zhang, Jianbo,Zhou, Le
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supporting information
p. 1419 - 1426
(2019/07/15)
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- Montmorillonite-catalyzed glysosylation of alcohols with glycals derived from galactose and glucose under microwave-induced reactions
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Montmorillonite K10-catalyzed glycosylation of alcohols with glycals obtained from galactose and glucose is performed efficiently using microwave irradiation with good anomeric selectivity.
- Yadav, Ram Naresh,Banik, Indrani,Banik, Bimal Krishna
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p. 1385 - 1387
(2020/06/27)
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- Structure-based design, synthesis and antitumoral evaluation of enulosides
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Enulosides, carbohydrate derivatives containing an α,β-unsaturated carbonyl unit, were designed and obtained in high yields and isomeric purity. All synthesized compounds exhibited antitumoral activity in micromolar range against four tested tumor cells lines, being the best results observed for HL-60?cells. These compounds open new possibilities to prepare an array of more active, site-specific or selective antitumor agents. 2016 Elsevier Ltd. All rights reserved.
- Santos, Jonh A.M.,Santos, Cosme S.,Almeida, Claudia L.A.,Silva, Thiago D.S.,Freitas Filho, Jo?o R.,Milit?o, Gardenia C.G.,da Silva, Teresinha G.,da Cruz, Carlos H.B.,Freitas, Juliano C.R.,Menezes, Paulo H.
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p. 192 - 201
(2017/02/15)
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- Magnetic core-shell Fe3O4@C-SO3H as an efficient and renewable 'Green catalyst' for the synthesis of O-2,3-unsaturated Glycopyra-nosides
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A magnetic core-shell solid-acid catalyst Fe3O4@C-SO3H was studied for synthesis of O-2,3-unsaturated glycosides through Ferrier rearrangement. The donors include 3,4,6-tri-O-acetyl-D-glucal and 3,4-di-O-acetyl-L-rhamnal. The acceptors consist of primary alcohols, secondary alcohols, tert-butanol, unsaturated alcohols, halogenated alcohol, sterol, sugars, and phenols. O-2,3-Unsaturated glycosides were obtained rapidly (5:1 to 19:1). Moreover, the catalyst can be easily separated from the reaction with an external magnetic force and reused for a minimum of five times without any significant decrease in the yields of the products after every recycle, suggesting it a promising green catalyst in 2,3-unsaturated glycosides syntheses.
- Sun, Guosheng,Qiu, Saifeng,Ding, Zekun,Chen, Heshan,Zhou, Jiafen,Wang, Zhongfu,Zhang, Jianbo
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supporting information
p. 347 - 352
(2017/02/10)
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- Gd(OTf)3 catalyzed preparation of 2,3-unsaturated O-, S-, N-, and C-pyranosides from glycals by Ferrier Rearrangement
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By using Gd(OTf)3 as the catalyst, synthesis of 2,3-unsaturated-glycosides has been performed by Ferrier Rearrangement. A series of 2,3-unsaturated O-, S-, N-, and C-glycosides were obtained from 3,4,6-tri-O-acetyl-d-glucal, 3,4,6-tri-O-benzyl-d-glucal, and 3,4-di-O-acetyl-l-rhamnal under mild reaction conditions in good yields and high anomeric selectivities.
- Chen, Peiran,Su, Jie
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supporting information
p. 84 - 94
(2015/12/23)
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- Hafnium(IV) triflate as a highly efficient catalyst for Ferrier rearrangement of O- and S-nucleophiles with glycals
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A highly efficient method to afford 2,3-unsaturated glycosides was described. In the presence of Hafnium(IV) triflate, a variety of 2,3-unsaturated-O- and S-glycosides have been obtained by stereoselective glycosylation of 3,4,6-tri-O-acetyl-d-glucal and hexa-O-acetyl-d-lactal with various acceptors in good isolated yields.
- Liu, Yonghui,Song, Tianbang,Meng, Weijia,Xu, Yun,Wang, Peng George,Zhao, Wei
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supporting information
p. 2758 - 2762
(2016/06/09)
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- Y(OTf)3 as a highly efficient catalyst in Ferrier Rearrangement for the synthesis of O- and S-2,3-unsaturated glycopyranosides
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By using Y(OTf)3 as the catalyst, a series of 2,3-unsaturated-glucosides have been synthesized from 3,4,6-tri-O-acetyl-d-glucal, 3,4-di-O-acetyl-l-rhamnal, and 3,4,6-tri-O-benzyl-d-glucal under mild reaction conditions in good yields with high anomeric selectivities. It was found that, in this reaction, 3,4,6-tri-O-benzyl-d-glucal behaved differently from the other two glucals when it was reacted with phenol, O-benzyl glucoside instead of O-phenyl glucoside formed as the sole product. An explanation is given for this phenomenon.
- Chen, Peiran,Li, Shan
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supporting information
p. 5813 - 5816
(2015/02/19)
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- Sm(OTf)3as a highly efficient catalyst for the synthesis of 2,3-unsaturated O- and S-pyranosides from glycals and the temperature-dependent formation of 4-O-acetyl-6-deoxy-2,3-unsaturated S-pyranosides and 4-O-acetyl-6-deoxy-3-alkylthio glycals
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By using Sm(OTf)3as the catalyst, synthesis of 2,3-unsaturated-glycosides has been performed. A series of 2,3-unsaturated glycosides were obtained from 3,4,6-tri-O-acetyl-d-glucal or 3,4-di-O-acetyl-l-rhamnal under mild reaction conditions in g
- Chen, Peiran,Zhang, Dalin
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p. 8505 - 8510
(2014/12/10)
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- An efficient procedure for the synthesis of 2,3-unsaturated-O-glycosides: TiCl3(OTf) as the catalyst for type i Ferrier rearrangement
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An efficient type I Ferrier rearrangement reaction system for the synthesis of 2,3-unsaturated-O-glycosides has been established by using TiCl 3(OTf) as the catalyst. A series of 2,3-unsaturated-O-glucosides were prepared from 3,4,6-tri-O-acetyl-d-glucal in good yield and high anomeric selectivity.
- Chen, Peiran,Lin, Lei
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p. 4524 - 4531
(2013/06/27)
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- CF3SO3H-SiO2 as catalyst for Ferrier rearrangement: An efficient procedure for the synthesis of pseudoglycosides
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An efficient method for the conversion of 2,4,6-tri-O-acetyl-D-glucal to 2,3-unsaturated glycosides by using triflic acid on SiO2 as catalyst has been established. A series of 2,3-unsaturated glucosides were synthesized in good yield and high anomeric selectivity under transition metal-free conditions.
- Chen, Peiran,Wang, Shaoshan
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supporting information
p. 583 - 588
(2013/07/25)
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- RuCl3·3H2O as catalyst for Ferrier rearrangement: An efficient procedure for the preparation of pseudoglycosides
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By using RuCl3·3H2O as catalyst, an improved method for the synthesis of 2,3-unsaturated-glycosides has been established. A series of 2, 3-unsaturated-glucosides were obtained from 2,4,6-tri-O-acetyl-d- glucal or 3,4-di-O-acetyl-6-deoxy-l-glucal in good yield and high anomeric selectivity.
- Chen, Peiran,Lin, Lei
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supporting information
p. 10045 - 10051
(2013/11/06)
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- Stereoselective synthesis of pseudoglycosides catalyzed by TeCl4 under mild conditions
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Catalytic amounts of tellurium(IV) tetrachloride were used to promote the O-glycosylation of 3,4,6-tri-O-acetyl-d-glucal to give the corresponding 2,3-unsaturated-O-glycosides. With simple alcohols, the desired compounds were obtained in good yields and excellent anomeric selectivity in a short reaction time using only 2 mol % of the catalyst. The application of the method in the synthesis of a small set of glycopyranosides with rigid or flexible linkers gave the corresponding α anomers as products in good yields. Further applications of some of the synthesized compounds in allylation reaction of aldehydes gave the corresponding homoallylic alcohols in good yields.
- Freitas, Juliano C. R.,Couto, Tulio R.,Paulino, Antonio A. S.,Malvestiti, Ivani,Oliveira, Roberta A.,Menezes, Paulo H.,De Freitas Filho, Joao R.
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p. 10611 - 10620,10
(2012/12/12)
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- Stereoselective synthesis of pseudoglycosides catalyzed by TeCl4 under mild conditions
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Catalytic amounts of tellurium(IV) tetrachloride were used to promote the O-glycosylation of 3,4,6-tri-O-acetyl-d-glucal to give the corresponding 2,3-unsaturated-O-glycosides. With simple alcohols, the desired compounds were obtained in good yields and excellent anomeric selectivity in a short reaction time using only 2 mol % of the catalyst. The application of the method in the synthesis of a small set of glycopyranosides with rigid or flexible linkers gave the corresponding α anomers as products in good yields. Further applications of some of the synthesized compounds in allylation reaction of aldehydes gave the corresponding homoallylic alcohols in good yields.
- Freitas, Juliano C.R.,Couto, Túlio R.,Paulino, Ant?nio A.S.,De Freitas Filho, Jo?o R.,Malvestiti, Ivani,Oliveira, Roberta A.,Menezes, Paulo H.
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p. 8645 - 8654
(2012/10/29)
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- Iron(III) triflate, a new efficient catalyst for Type i Ferrier Rearrangement
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By using iron(III) triflate as catalyst, an improved method for the synthesis of 2,3-unsaturated-O-glycosides has been established. A series of 2,3-unsaturated-O-glucosides were obtained from 2,4,6-tri-O-acetyl-d-glucal in good yield and high anomeric selectivity.
- Chen, Peiran,Wang, Shaoshan
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supporting information; experimental part
p. 5356 - 5362
(2012/09/07)
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- A new stereocontrolled synthetic route to (-)-echinosporin from d-glucose via Padwa allenylsulfone [3 + 2]-anionic cycloadditive elimination
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A new formal total synthesis of (-)-echinosporin has been developed based upon the Padwa [3 + 2]-cycloadditive elimination reaction of allenylsulfone 4 with the d-glucose-derived enone 14 which provides cycloadduct 12.
- Flasz, Jakub T.,Hale, Karl J.
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supporting information; experimental part
p. 3024 - 3027
(2012/08/07)
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- Efficient pseudo-enantiomeric carbohydrate olefin ligands
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Highly efficient pseudo-enantiomeric olefin ligands were designed from d-glucose and d-galactose. These ligands yield consistently excellent levels of enantioselectivity in Rh(I)-catalyzed 1,4-additions of aryl- and alkenylboronic acids to achiral enones and high diastereoselectivity with chiral substrates. Contrary to established olefin ligands, they are obtained enantiomerically pure via short syntheses without racemic resolution steps, making them a valuable addition to the arsenal of chiral ligands with olefinic donor sites.
- Grugel, Holger,Albrecht, Fabian,Minuth, Tobias,Boysen, Mike M. K.
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scheme or table
p. 3780 - 3783
(2012/09/08)
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- Amine-linked diglycosides: Synthesis facilitated by the enhanced reactivity of allylic electrophiles, and glycosidase inhibition assays
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Diglycose derivatives, consisting of two monosaccharides linked at non-anomeric positions by a bridging nitrogen atom, have been synthesised. Conversion of one of the precursor monosaccharide coupling components into an unsaturated derivative enhances its
- Cumpstey, Ian,Frigell, Jens,Pershagen, Elias,Akhtar, Tashfeen,Moreno-Clavijo, Elena,Robina, Inmaculada,Alonzi, Dominic S.,Butters, Terry D.
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supporting information; experimental part
p. 1115 - 1123
(2011/10/08)
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- A facile H2SO4/4 ? molecular sieves catalyzed synthesis of 2,3-unsaturated O -glycosides via ferrier-type rearrangement
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A novel method for synthesizing 2,3-unsaturated glycosides has been developed using a metal-free catalytic system. This catalyst, sulfuric acid/4 molecular sieves can catalyze the reaction of 3,4,6-tri-O-acetyl-d-glucals and a wide range of alcohols at room temperature, affording 2,3-unsaturated glycosides in good -selectivity (α/β> 6:1) via a Ferrier-type rearrangement. Georg Thieme Verlag Stuttgart - New York.
- Zhou, Jiafen,Zhang, Bo,Yang, Guofang,Chen, Xuan,Wang, Qingbing,Wang, Zhongfu,Zhang, Jianbo,Tang, Jie
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experimental part
p. 893 - 896
(2010/07/16)
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- H2SO4-SiO2: Highly efficient and novel catalyst for the Ferrier-type glycosylation
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Sulfuric acid immobilized on silica gel is designed as a very useful catalyst for synthesis of 2,3-unsaturated glycopyranosides. This handy, metal-free, environment friendly transformation provides high yields and α-stereoselectivities in a very few amount (0.02 eq.) of catalyst and in short reaction times (10 min).
- Zhou, Jia Fen,Chen, Xuan,Wang, Qing Bing,Zhang, Bo,Zhang, Li Yan,Yusulf, Abdullh,Wang, Zhong Fu,Zhang, Jian Bo,Tang, Jie
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experimental part
p. 922 - 926
(2011/11/12)
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- Convertible formation of different glycoside using molecular iodine
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The observation of convertible formation between 2-deoxy-2-iodo-O- glycosides and 2,3-unsaturated glycoside was described. The selective formation of 2-deoxy-2-iodo-O-glycosides was found from the reaction of D-glucal with iodine in the excess alcohol acceptor or the addition of ceric ammonium nitrate as additive while the addition of a stoichiometric amount of alcohol in solvent favored 2,3-unsaturated glycosides formation. The Japan Institute of Heterocyclic Chemistry.
- Saeeng, Rungnapha,Sirion, Uthaiwan,Sirichan, Yada,Trakulsujaritchok, Thanida,Sahakitpichan, Poolsak
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experimental part
p. 2569 - 2580
(2011/04/22)
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- Novel olefin-phosphorus hybrid and diene ligands derived from carbohydrates
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Starting from readily available monosaccharides d-glucose and d-arabinose, a family of novel chiral diene and olefin-phosphinite hybrid ligands has been designed. These ligands were prepared by attaching phosphinite or allylic donor sites onto unsaturated carbohydrate scaffolds. In rhodium(I)-catalysed conjugate addition of boronic acids to enones, the olefin-phosphinite hybrids gave products in up to 99% ee and above, whereas the dienes only led to modest enantioselectivity. However, by shifting the allylic donor sites from position 4 of the pyranose to the anomeric centre, an unexpected reversal of the stereoinduction process was observed. Georg Thieme Verlag Stuttgart New York.
- Grugel, Holger,Minuth, Tobias,Boysen, Mike M. K.
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experimental part
p. 3248 - 3258
(2010/11/18)
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- ZnCl2/alumina impregnation catalyzed Ferrier rearrangement: an expedient synthesis of pseudoglycosides
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An improved method for the synthesis of 2,3-unsaturated-O-glycosides has been developed. ZnCl2 impregnated on activated alumina acts as an excellent reagent system for the conversion of 2,4,6-tri-O-acetyl-d-glucal to 2,3-unsaturated-O-glycosides with high α-selectivity.
- Gorityala, Bala Kishan,Lorpitthaya, Rujee,Bai, Yaguang,Liu, Xue-Wei
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experimental part
p. 5844 - 5848
(2009/12/01)
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- Kinetically controlled Ferrier rearrangement of 3-O-mesyl-d-glycal derivatives
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The Ferrier rearrangement, which is widely used in carbohydrate chemistry, is generally performed under acidic conditions to give an α anomer with high stereoselectivity. We have found that 3-O-mesyl-d-glycals 2-4 were smoothly reacted with alcohols in th
- Watanabe, Yuhya,Itoh, Tsubasa,Sakakibara, Tohru
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scheme or table
p. 516 - 520
(2009/05/11)
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- Ferric sulfate hydrate-catalyzed O-glycosylation using glycals with or without microwave irradiation
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We have developed a novel glycal-based O-glycosylation reaction, in which the substrates are not only peracetyl glycals but also perbenzyl glucals to afford the corresponding 2,3-unsaturated-O-glycosides via Ferrier rearrangement. The reaction of the perbenzyl glucal with various alcohols catalyzed by ferric sulfate hydrate (Fe2(SO4)3·xH2O) was successfully carried out to give 2,3-unsaturated d-O-glucosides with exclusive α-selectivity and no formation of addition products 2-deoxy hexopyranosides was observed. It is the first report on peralkyl glycal efficiently undergoing Ferrier rearrangement instead of addition of alcohols catalyzed by Lewis acids. Fe2(SO4)3·xH2O is an effective, convenient, and environmentally benign heterogeneous catalyst. It has low catalytic loading and recyclable without significant loss of activity.
- Zhang, Guisheng,Liu, Qingfeng,Shi, Lei,Wang, Jiuxia
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p. 339 - 344
(2008/09/16)
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- Ferric sulphate hydrate-catalyzed, microwave-assisted synthesis of 2,3-unsaturated O-glycosides via the Ferrier reaction
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Fe2(SO4)3·xH2O catalyzes the Ferrier reaction of per-O-acetylated/benzylated glycals with alcohols to give 2,3-unsaturated α-glycosides in a few minutes under microwave irradiation. Copyright Taylor & Francis Group, LLC.
- Zhang, Guisheng,Liu, Qingfeng
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p. 3485 - 3492
(2008/03/11)
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- Exclusive formation of α-anomers in NbCl5-promoted ferrier rearrangement for the synthesis of 2,3-unsaturated glycosides
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NbCl5-catalyzed reaction of primary and secondary alcohols with tri-O-lacetyl-d-glucal is described. Exclusive formation of α-anomers of eight 2,3-unsaturated glycosides (3a-h) in high yields has been observed. Among eight unsaturated glycosides (3a-h) prepared, two of them (3d,e) are new. A new mechanism of the formation of (3a-h) from tri- O-acetyl-d-glucal and an alcohol assisted by NbCl5 as a catalyst has been suggested.{A figure is presented}. α-Unsaturated Glycoside NbCl5 Tri-O-acetyl-D-glucal Ferrier Rearrangement.
- de Oliveira, Ronaldo N.,de Melo, Adriana C.N.,Srivastava, Rajendra M.,Sinou, Denis
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p. 2607 - 2613
(2008/02/04)
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- Microwave-enhanced Ferrier reaction: A facile synthesis of 2,3-unsaturated-O-glycosides under solvent-free conditions
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A variety of 2,3-unsaturated- O -glycosides have been prepared by the Ferrier rearrangement of acetyl protected glycals under microwave irradiation using silica gel as an acid catalyst. Environmental friendliness, high yields, and short reaction times are the key features of this method. Furthermore, the method was applicable not only to the Ferrier reaction of 3,4,6-tri- O -acetyl glucal and 3,4,6-tri- O -acetyl galactal but also to the Ferrier reaction of 3,4-di- O -acetyl arabinal. Copyright Taylor & Francis Group, LLC.
- Du, Wenting,Hu, Yongzhou
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p. 2035 - 2046
(2007/10/03)
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- Ferrier rearrangement catalyzed by HClO4-SiO2: Synthesis of 2,3-unsaturated glycopyranosides
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Alkyl 2,3-unsaturated glycopyranosides have been prepared by the Ferrier rearrangement of acetyl protected glycals catalyzed by HClO4-SiO 2. Operational simplicity, use of economically convenient catalyst, mild reaction conditions, high yields, short reaction times are the key features of this protocol.
- Misra, Anup Kumar,Tiwari, Pallavi,Agnihotri, Geetanjali
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p. 260 - 266
(2007/10/03)
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- TRANSACETALISATION PROCESS
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The invention relates to the resolution of racemic mixtures, and in particular to the separation of enantiomers of chiral alcohols utilising recyclable chiral auxiliaries. The present invention also relates to a process for preparing these recyclable chiral auxiliaries using an enantiomerically pure alcohol.
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Page/Page column 43-44
(2010/02/13)
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- A new bismuth nitrate-induced stereospecific glycosylation of alcohols
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Bismuth nitrate-catalyzed stereospecific glycosylation of alcohol with glycal has been developed.
- Banik, Bimal K.,Adler, Dorothy,Nguyen, Phuong,Srivastava, Neeta
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p. 101 - 104
(2007/10/03)
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- Synthesis, Configurational and Conformational Studies of Six Amino Sugar Precursors Formed by [3+2] Cycloaddition of Alkylnitrile Oxides to Enone Sugars
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An easy and efficient synthesis of a novel bicyclic system (isoxazolino-pyranoside), obtained by the 1,3-dipolar cycloaddition of acetonitrile and propionitrile oxides to highly reactive α,β-unsaturated sugar enones, is described. The configuration and co
- Filho, Joao R. de Freitas,Cottier, Louis,Srivastava, Rajendra M.,Sinou, Denis
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p. 1358 - 1360
(2007/10/03)
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- Iodine catalyzes C-glycosidation of D-glucal with silylacetylene
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A convenient method for C-glycosidation (alkynylation) with various silylacetylenes to D-glucal by iodine molecule via iodo-oxonium intermediates provided exclusively the α-acetylene glycoside products. Eleven successful examples are shown under this cond
- Saeeng, Rungnapha,Sirion, Uthaiwan,Sahakitpichan, Poolsak,Isobe, Minoru
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p. 6211 - 6215
(2007/10/03)
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- Microwave-induced, Montmorillonite K10-catalyzed Ferrier rearrangement of tri-O-acetyl-D-galactal: Mild, eco-friendly, rapid glycosidation with allylic rearrangement
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Montmorillonite K10 was found to catalyze, under microwave irradiation, rapid O-glycosidation of 3,4,6-tri-O-acetyl-D-galactal to afford exclusively the alkyl and aryl 2,3-dideoxy-D-threo-hex-2-enopyranosides with very high α-selectivity and without the formation of the 2-deoxy-D-lyxo-hexopyranosides. Under these conditions, 3,4,6-tri-O-acetyl-D-glucal as usual also underwent the Ferrier rearrangement.
- Shanmugasundaram, Bhagavathy,Bose, Ajay K.,Balasubramanian, Kalpattu K.
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p. 6795 - 6798
(2007/10/03)
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- Highly stereoselective synthesis of pseudoglycals via Yb(OTf)3 catalyzed Ferrier glycosylation
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The reaction of tri-O-acetyl-D-glucal with various alcohols and thiols was effectively promoted by a catalytic amount of Yb(OTf)3 to produce a variety of pseudoglycals via Ferrier rearrangement in excellent yields and anomeric selectivity.
- Takhi,Abdel-Rahman,Schmidt
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p. 427 - 429
(2007/10/03)
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- Scandium triflate catalyzed ferrier rearrangement: An efficient synthesis of 2,3-unsaturated glycopyranosides
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Scandium(III) trifluoromethanesulfonate is found to catalyze efficiently the O-glycosidation of 3,4,6-tri-O-acetyl-D-glucal with various alcohols and phenols to afford the corresponding 2,3-unsaturated glycosides in excellent yields with good anomeric selectivity.
- Yadav,Reddy,Murthy,Kumar
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p. 1450 - 1451
(2007/10/03)
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- Novel optically active 1,3-aminoalcohols derived from D-glucal
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A series of ethyl(phenyl) 6-amino-2,3,6-trideoxy-α-D-glucopyranosides (amino = piperidino (Pip), pyrrolidino (Pyr), azetidino (Az), Bu2N) have been prepared from tri-O-acetyl-D-glucal to obtain catalysts for asymmetric synthesis and the starting compounds for the syntheses of other bidentate ligands.
- Iovel,Oehme,Michalik,Lukevics
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- Radical-mediated construction of cyclopentane with concurrent formation of a well-defined quaternary center
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Synthetic efforts toward the total synthesis of clavulactone dealing with enantioselective construction of the cyclopentane moiety are reported. With a novel radical-mediated cyclization as key step, the current approach allows for concurrent enantioselective construction of a quaternary chiral carbon at the cyclization step. The stereochemistries of the newly formed chiral centers are dictated by the configuration of the C-1 (cf. numbering in 1). The high selectivity observed in this work is ascribed to the conformational advantage of the cyclic acetal, which results in a much better defined transition state than the previously used open-chain counterpart does.
- Zhu,Qiao,Wu,Wu
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p. 2428 - 2432
(2007/10/03)
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- Synthesis of Conjugated α-D-Hexenopyranosiduloses
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α-Enone sugars such as 2,3-dideoxy-α-D-hex-2-enopyranosid-4-uloses I and 2,4-dideoxy-α-D-hex-3-enopyranosid-2-uloses II involving the corresponding C-2 and C-4 methylated sugars 5, 10a and 10b were successfully synthesized from D-glucose in high yields by
- Liang, David Woei-Ming,Lin, Shu-Fu,Yap, Wen-Yen,Deng, Yea-Wen
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p. 175 - 180
(2007/10/02)
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- Synthesis of 2-amino-2-deoxy-D-hexopyranosides from 4-O-trichloroacetimidyl-D-hex-2-enopyranoside by [3,3]-sigmatropic rearrangement
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2-Amino-2-deoxysugars, D-mannosamine and D-altrosamine derivatives were synthesized together with D-idosamine and D-talosamine ones from a 2-deoxy-2-trichloroacetamido-hex-3-enopyranoside. This key intermediate was prepared by regio- and stereoselective [
- Takeda, Kazuyoshi,Kaji, Eisuke,Konda, Yaeko,Sato, Noriko,Nakamura, Hiroko,Miya, Noriko,Morizane, Aya,Yanagisawa, Yuko,Akiyama, Akira,Zen, Shonosuke,Harigaya, Yoshihiro
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p. 7145 - 7148
(2007/10/02)
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- Radical Cyclization of Some Unsaturated Carbohydrate-Derived Acetals
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Treatment of halogeno acetals derived from deoxy-D-hexenopyranosides of erythro and threo configuration with tributyltin hydride with a radical initiator gave fused pyranofuranosides.This allowed the completely stereo and regio-specific introduction of a
- Moufid, Nadira,Chapleur, Yves,Mayon, Patrick
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p. 991 - 998
(2007/10/02)
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- UNSATURATED CARBOHYDRATES. PART 29 THEIR APPLICATION TO THE SYNTHESIS OF STEREOSPECIFICALLY DOUBLY AND TRIPLY BRANCHED DERIVATIVES
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Treatment of 2,3-dideoxy-α-D-erythro-hex-2-enopyranosyl derivatives having 2-haloethyl substituents separately at O-1 and O-4 with tri-n-butyltin hydride together with a radical initiator gave products 16 and 5,6 with tetrahydrofuranyl rings cis-fused to
- Ferrier, Robert J.,Petersen, Paul M.
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- Radical Cyclisation Reactions leading to Doubly Branched Carbohydrates and 6- and 8-Oxygenated 2,9-Dioxabicyclononane Derivatives
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2,3-Dideoxy-α-D-erythro-hex-2-enopyranosyl derivatives having, separately, 2-halogenoethyl substituents at O-1 and O-4, on treatment with tri-n-butyltin hydride together with a radical promoter, gave products with tetrahydrofuranyl rings cis-fused to C-1, C-2 and C-3, C-4, i.e. with branched-points at C-2 and C-3, respectively, and similar reactions in the presence of methyl acrylate or allyltributyltin gave main products with the same bicyclic structures but with additional branch points at C-3 and C-2; when applied to a 2-bromo-1-methoxyethyl 2,3-dideoxyhex-2-enopyranoside and to a 2-bromoethyl 3-deoxyhex-2-enopyranoside the ring closure reactions afforded 8- and 6-oxygenated 2,9-dioxabicyclononane derivatives.
- Ferrier, Robert J.,Petersen, Paul M.,Taylor, Mark A.
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p. 1247 - 1248
(2007/10/02)
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- The preparation of amino sugars and branched-chain sugars by palladium-catalyzed allylic substitution of alkyl hex-2-enopyranosides
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Ethyl 4,6-di-O-acetyl-2,3-dideoxy-α-D-erythro-hex-2-enopyranoside (1) in the presence of triphenylphosphine and a catalytic amount of tetrakis(triphenylphosphine)palladium(0) reacted with a variety of amines or with reactive methylene compounds to give high yields of products aminated or C-alkylated, respectively, in allylic position.Some analogous experiments were performed using the β-D-erythro anomer (2) and the α-D-threo epimer (3) of 1.The constitutions and configurations of the new products were established by means of mass spectra, 13C- and 1H-nmr spectra, and optical rotation data.The reactions of 1 were found to be highly regio- and stereoselective, giving almost exclusively 4-substituted 2-enopyranosides with retention of configuration, except in the case of dibenzylamine which produced a mixture of the corresponding enoside and its 2-substituted, 3,4-unsaturated isomer ahving the α-D-threo configuration.The reactions of 2 appeared slightly less selective although they, too, furnished mainly 4-substituted 2-enopyranosides with retention of configuration.Regioselectivity was low or lacking in two C-alkylations performed with 3, which gave mixtures of 4-substituted 2-enosides and 2-substituted 3-enosides.Some aspects of conformation and optical rotation in enopyranosides are discussed.
- Baer, Hans H.,Hanna, Zaher S.
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p. 889 - 906
(2007/10/02)
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