Stannous Triflate Research Articles

Sn(OTf)2 as an Effective Lewis Acid in Reactions of Cyclopropyl Ketones with Acetic Anhydride: Application in the Synthesis of a 19‐Nor‐B‐homo Steroid

AbstractAttempts to convert 3β‐acetoxy‐5,19‐cyclo‐pregna‐6,20‐dione (8) into a cyclocitrinol‐related steroid with a bicyclo[4.4.1]‐undecane AB‐ring substructure through a Lewis acid‐assisted fragmentation failed. Instead, treating 8 with an excess of Ac2O and BF3·Et2O afforded B‐homo steroid 9 in 90 % yield. This unexpected rearrangement is assumed to proceed via an intermediate bicyclobutonium cation. Remarkably, tricyclo[4.4.1.0]undecane‐1‐one (rac‐13), prepared as a model substrate, did not react under the same conditions. However, by screening various Lewis acids, stannous triflate was identified as a particularly efficient reagent for this and related Lewis acid‐assisted ring‐opening reactions of cyclopropyl ketones in the presence of Ac2O, and even catalytic amounts of Sn(OTf)2 (5 mol‐%) proved to be effective.

Synthesis of a Star Polymer Library with a Diverse Range of Highly Functionalized Macromolecular Architectures

An efficient and versatile synthetic route toward highly functionalized core cross-linked star (CCS) polymers with interesting structures and properties is presented using an alkyne CCS polymer as scaffold. The alkyne CCS polymer scaffold was initially prepared via an improved arm-first approach, through ring-opening polymerization (ROP) of 4,4′-bioxepanyl-7,7′-dione (BOD) with a poly(caprolactone-b-propargyl methacrylate) macroinitiator and stannous triflate (Sn(OTf)2) catalyst. Highly functionalized fluorescent, saccharide and amphiphilic CCS polymers were synthesized by grafting the alkyne CCS polymer with the corresponding azido substituted compounds via copper catalyzed 1,3-dipolar azide−alkyne cycloaddition (CuAAC), ‘click’ chemistry. The resulting corona-functionalized CCS polymers were characterized via GPC, 1H NMR spectroscopic analysis and DLS. 1H NMR spectroscopic analysis revealed that the grafting efficiency (i.e., click efficiency) ranged from 10 to >99% and was highly dependent on the structure and functionality of the azido compounds. This equates to the grafting of 45 to 450 functional compounds onto the CCS polymer scaffolds corona. The results indicate that the click functionalization efficiency is closely related to the molecular size of the azido compounds. Other than size, factors including molecular structure, compatibility and synergistic driving forces, such as the formation of potential inclusion complexes, are also found to affect the functionalization efficiencies.

Synthesis of the Sialyloligosaccharide Gal-β(1→3)-[Neu5Ac-α(2→6)]-GalNAc, The Epitope of the Tumor-Associated Glycoprotein Tag 72

Abstract Benzyl 2-acetamido-2-deoxy-4,6-O-(4-methoxybenzylidene)-β-D-glucopyrano-side (3) was glycosylated with 2,3,4,6-tetra-O-acetyl-α-D-galactopyranosyl bromide (2) to give disaccharide 4. Reductive ring-opening of the acetal group provided as a major compound (64%) the 6-O-(4-methoxybenzyl) derivative (5) which was directly converted into benzyl 2-acetamido-3-O-(2,3,4,6-tetra-O-acetyl-β-D-galactopyranosyl)-4-O-benzoyl-2-deoxy-β-D-galactopyranoside (10) through triflate displacement by tetra-n-butylammonium benzoate, followed by removal of the 4-methoxybenzyl ether group. The minor compound (30%) (6) could be also converted into 10 through the 6-O-(tert-butyldimethylsilyl) ether 8 which was treated similarly to compound 5. Stannous triflate promoted condensation of methyl (5-acetamido 4,7,8,9-tetra-O-acetyl-2,3,5-trideoxy-D-glycero-β-D-galacto-2-nonulopyranosyl chloride)onate (12) with the glycosyl acceptor 10, in tetrahydrofuran, afforded a 3:1 mixture of a and β (2→6) linked trisaccharides 13 and 14 in 44% isolated yield (63% based on starting material recovery). Removal of the protecting groups led to trisaccharide Gal-β(l→3)-[Neu5Ac-α(2→6)]-GalNAc (1), the epitope of the tumor-associated glycoprotein TAG 72.

ChemInform Abstract: The Synthesis of 2′‐Deoxy‐β‐disaccharides: Novel Approaches.

Abstract Benzylated 1,2-orthoacetates were converted by dry acetic acid into 1,2- trans -diacetates which behaved as excellent β-glycosyl donors with various non-acylated glycosyl acceptors in the presence of trimethylsilyl triflate. Deacetylation, followed by xanthation and then radical reduction with tributylstannane, led in high yields to the 2′-deoxy-β-disaccharides. In another approach, glycosylations were performed with various derivatives of N -formylglucosamine (β-acetate or α-trichloroacetimidate, in the presence of trimethylsilyl triflate; α-chloride in the presence of silver or stannous triflate) upon acceptors having different kinds of protecting groups. The resulting disaccharides were smoothly deaminated into the corresponding 2′-deoxy-β-disaccharides through intermediate isonitriles by radical reduction with tributylstannane. The β-stereocontrol in the glycosylation step was ensured by an intermediate oxazolinium ion. A β-trichloroacetimidate of N -phthaloylglucosamine was used as a more powerful glycosylating reagent in the case of acid-sensitive molecules, with the conversion of the N -phthaloyl into an N -formyl group being effected in a high yield after the glycosylation step.

The synthesis of 2′-deoxy-β-disaccharides: Novel approaches

Benzylated 1,2-orthoacetates were converted by dry acetic acid into 1,2- trans-diacetates which behaved as excellent β-glycosyl donors with various non-acylated glycosyl acceptors in the presence of trimethylsilyl triflate. Deacetylation, followed by xanthation and then radical reduction with tributylstannane, led in high yields to the 2′-deoxy-β-disaccharides. In another approach, glycosylations were performed with various derivatives of N-formylglucosamine (β-acetate or α-trichloroacetimidate, in the presence of trimethylsilyl triflate; α-chloride in the presence of silver or stannous triflate) upon acceptors having different kinds of protecting groups. The resulting disaccharides were smoothly deaminated into the corresponding 2′-deoxy-β-disaccharides through intermediate isonitriles by radical reduction with tributylstannane. The β-stereocontrol in the glycosylation step was ensured by an intermediate oxazolinium ion. A β-trichloroacetimidate of N-phthaloylglucosamine was used as a more powerful glycosylating reagent in the case of acid-sensitive molecules, with the conversion of the N-phthaloyl into an N-formyl group being effected in a high yield after the glycosylation step.

The Catalytic Asymmetric Michael Reaction of Tin(II) Enethiolates

Abstract The catalytic asymmetric Michael reaction of tin(II) enethiolates forming 5-oxodithioesters in high yield with moderate to good enantioselectivity is achieved by employing catalytic amounts of stannous triflate and chiral diamine.

ChemInform Abstract: Stannous Triflate Mediated Glycosidations. A Stereoselective Synthesis of 2‐Amino‐2‐deoxy‐β‐D‐glucopyranosides Directly with the Natural N‐Acetyl Protecting Group.

ChemInformVolume 19, Issue 12 Natural Products ChemInform Abstract: Stannous Triflate Mediated Glycosidations. A Stereoselective Synthesis of 2-Amino-2-deoxy-β-D-glucopyranosides Directly with the Natural N-Acetyl Protecting Group. A. LUBINEAU, A. LUBINEAU Lab. Chim. Org. Multifonct., Ass. CNRS, Univ Paris-Sud, 91405 Orsay, FranceSearch for more papers by this authorJ. LE GALLIC, J. LE GALLIC Lab. Chim. Org. Multifonct., Ass. CNRS, Univ Paris-Sud, 91405 Orsay, FranceSearch for more papers by this authorA. MALLERON, A. MALLERON Lab. Chim. Org. Multifonct., Ass. CNRS, Univ Paris-Sud, 91405 Orsay, FranceSearch for more papers by this author A. LUBINEAU, A. LUBINEAU Lab. Chim. Org. Multifonct., Ass. CNRS, Univ Paris-Sud, 91405 Orsay, FranceSearch for more papers by this authorJ. LE GALLIC, J. LE GALLIC Lab. Chim. Org. Multifonct., Ass. CNRS, Univ Paris-Sud, 91405 Orsay, FranceSearch for more papers by this authorA. MALLERON, A. MALLERON Lab. Chim. Org. Multifonct., Ass. CNRS, Univ Paris-Sud, 91405 Orsay, FranceSearch for more papers by this author First published: March 22, 1988 https://doi.org/10.1002/chin.198812336Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume19, Issue12March 22, 1988 RelatedInformation

Stannous triflate mediated glycosidations. A stereoselective synthesis of 2-amino 2-deoxy-β-D-glucopyranosides directly with the natural N-acetyl protecting group.

Various 2-acetamido 2-deoxy β-D-glucopyranosides have been prepared in good yield from the crystalline 2-acetamido 3,4,6-tri-O-acetyl 2-deoxy α-D-glucopyranosyl chloride using stannous triflate as promoter.

ChemInform Abstract: Asymmetric Allylation of Prochiral Aldehydes with a New Enantioselective Allylating Agent Prepared from Stannous Triflate, a Chiral Diamine, and Allyldialkylaluminum.

AbstractDie prochiralen Aldehyde (I) werden unter den angegebenen Bedingungen enantioselektiv in die entsprechenden sekundären Homoallylalkohole (II) übergeführt.

A NOVEL METHOD FOR THE STEREOSELECTIVE SYNTHESIS OF β-AMINOACID DERIVATIVES VIA TIN(II) CARBOXYLIC THIOESTER ENOLATES

Abstract Tin(II) carboxylic thioester enolates, formed in situ from stannous 2-methyl-2-propanethiolate and ketenes, react with imines in the presence of stannous triflate to give the corresponding β-aminocarboxylic thioesters in an anti-selective manner. This method is successfully applied to a diastereoselective synthesis of a carbapenem antibiotic PS-5 intermediate.

STANNOUS TRIFLATE MEDIATED ALDOL REACTION OF 3-(3-ALKOXY AND 3-AMINOPROPANOYL) THIAZOLIDINE-2-THIONES STEREOSELECTIVE SYNTHESIS OF β-LACTAM DERIVATIVES

Abstract The tin(II) enolate is generated from 3-acylthiazolidine-2-thione with β-alkoxy or β-amino functionality on treatment with stannous triflate in the presence of N-ethylpiperidine. The enolate further reacts with aldehyde to afford the aldol product with high syn-stereoselectivity. The aldol product thus produced is stereospecifically converted to β-lactam derivative with hydroxyethyl side chain.

ChemInform Abstract: A CONVENIENT METHOD FOR THE SYNTHESIS OF α-PHENYLTHIO-α,β-UNSATURATED KETONE BY STANNOUS TRIFLATE PROMOTED REARRANGEMENT OF α-SULFINYL KETONE

Die α-Sulfinylketone (I) bzw. die α-Sulfinylnitrile (VI) werden durch Umsetzung mit Zinn-triflat (II) in Gegenwart von Basen wie (III) oder (VII) und eines Silyl-Derivates wie (IV) oder (VIII) in die ungesättigten Ketone (V) bzw. Nitrile (IX) übergeführt.

Stannous triplate mediated glycosidations. A sterroselective synthesis of β - d[formula omitted

Various 1,2 trans,β- d -linked disaccharides with glucose as non-reducing unit have been prepared with complete stereoselectivity from acetobromoglucose and suitably protected sugar derivatives using stannous triflate as promoter.

A CONVENIENT METHOD FOR THE SYNTHESIS OF α-PHENYLTHIO-α,β-UNSATURATED KETONE BY STANNOUS TRIFLATE PROMOTED REARRANGEMENT OF α-SULFINYL KETONE

Abstract α-Phenylthio-α,β-unsaturated ketones are prepared in fairly good yields on treatment of α-sulfinyl ketone with stannous triflate. α-Phenylthio-α,β-unsaturated cyanides are also prepared from α-sulfinyl cyanides according to the similar procedure.

VERSATILE RELATIVE AND ABSOLUTE STEREOCONTROL IN STANNOUS TRIFLATE MEDIATED ALDOL-TYPE REACTIONS OF 3-(2-BENZYLOXYACETYL)THIAZOLIDINE-2-THIONE

Abstract In the stannous triflate mediated aldol-type reactions of 3-(2-benzyloxyacetyl)thiazolidine-2-thione, stereochemical course of the reactions is dramatically altered by the addition of tetramethylethylenediamine as a ligand. High asymmetric induction is also achieved by the addition of chiral diamine derived from l-prolin.

ChemInform Abstract: STANNOUS TRIFLATE MEDIATED ALDOL REACTION OF 3‐ACYLTHIAZOLIDINE‐2‐THIONE: A CONVENIENT METHOD FOR THE STEREOSELECTIVE SYNTHESES OF β‐HYDROXY ALDEHYDE AND β‐HYDROXY CARBOXYLIC ACID DERIVATIVES

Chemischer InformationsdienstVolume 14, Issue 23 Heterocyclic Compounds ChemInform Abstract: STANNOUS TRIFLATE MEDIATED ALDOL REACTION OF 3-ACYLTHIAZOLIDINE-2-THIONE: A CONVENIENT METHOD FOR THE STEREOSELECTIVE SYNTHESES OF β-HYDROXY ALDEHYDE AND β-HYDROXY CARBOXYLIC ACID DERIVATIVES T. MUKAIYAMA, Search for more papers by this authorN. IWASAWA, Search for more papers by this author T. MUKAIYAMA, Search for more papers by this authorN. IWASAWA, Search for more papers by this author First published: June 7, 1983 https://doi.org/10.1002/chin.198323234Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onEmailFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume14, Issue23June 7, 1983 RelatedInformation

ChemInform Abstract: STANNOUS TRIFLATE: A FACILE CROSS‐ALDOL REACTION BETWEEN TWO KETONES VIA DIVALENT TIN ENOLATES

AbstractAus den Ketonen (I) werden mit Zinn‐triflat (II) Enolate herge‐v stellt, die mit den Ketonen (III) zu den Hydroxyketonen (IV) führen.

STANNOUS TRIFLATE MEDIATED ALDOL REACTION OF 3-ACYLTHIAZOLIDINE-2-THIONE: A CONVENIENT METHOD FOR THE STEREOSELECTIVE SYNTHESES OF β-HYDROXY ALDEHYDE AND β-HYDROXY CARBOXYLIC ACID DERIVATIVES

Abstract Divalent tin enolates, formed from stannous triflate and 3-acylthiazolidine-2-thiones, react with aldehydes to afford the corresponding aldol products in high yields with high erythroselectivities. The adducts are easily transformed into β-hydroxy aldehyde and β-hydroxy carboxylic acid derivatives.

STANNOUS TRIFLATE: A FACILE CROSS-ALDOL REACTION BETWEEN TWO KETONES VIA DIVALENT TIN ENOLATES

Abstract Divalent tin enolates, formed from stannous triflate and ketones, react with a second ketone under mild conditions to afford the corresponding cross-aldol products in good to excellent yields. In the case of the cross-coupling with aromatic ketone, enhanced threo-selectivity was observed.

ChemInform Abstract: STANNOUS TRIFLATE: A NEW ALDOL REACTION VIA DIVALENT TIN ENOLATES

AbstractDie mit Hilfe von Zinn‐trifluormethansulfonat [Sn(O‐Tf)2] und tertiären Aminen wie N‐Ethylpiperidin aus Ketonen (I) gebildeten zweiwertigen Zinnenolate reagieren mit Aldehyden (II) zu entsprechenden Kreuzaldolprodukten (III) und (IV), wobei die ReaktlOn SIaIK stereosexextlv zugunsten ucr CIyLIuU‐V c1 uuluuxxgcu uu; vcuauu.