<i>trans,anti,trans</i>-Tetra(spirotetrahydrofuranyl)cyclohexane-1,2-dione. Stereocontrolled Synthesis and Definition of Its Susceptibility to Photoisomerization

Paquette, Leo A.; Lowinger, Timothy B.; Bolin, David G.; Branan, Bruce M.

doi:10.1021/jo960961p

Cited by 14 publications

(7 citation statements)

References 31 publications

(41 reference statements)

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“…Indeed, 24 predominates by a ratio of 5:1. Selenoxide elimination then afforded olefin 25 , the hydroxyl group in which was utilized to effect syn delivery of OsO 4 and m -chloroperbenzoic acid . Conversion to the triol occurred in a few hours with a selectivity of 4.7:1.…”

Section: Resultsmentioning

confidence: 99%

An Enantioselective Ring Expansion Route Leading to Furanose and Pyranose Nucleosides Featuring Spirodiketopiperazines at the Anomeric Position

1999

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A study directed at the enantioselective synthesis of spirodiketopiperazine homologues of hydantocidin is described. Furanoid glycals, systems that are amenable to C-5 metalation in the presence of tert-butyllithium, are readily coupled to N-protected 2,3-azetidinediones provided that at least 1 equiv of BF(3).OEt(2) is present to curb enolization. The resulting 1:1 mixtures of carbinols undergo smooth ring expansion to spirocyclic keto amides when heated with pyridinium p-toluenesulfonate in benzene. 1,2-Acyl shifts operate exclusively. Since attempts to engage these products in Beckmann rearrangement proved singularly unsuccessful, recourse was alternatively made to new methodology based upon sequential Baeyer-Villiger oxidation and ammonolysis. The data show that the first of these steps occurs with exclusive migration of the quaternary carbon. Furthermore, nucleophilic attack by NH(3) can be directed regioselectively to the anomeric region. If heating is supplied during acid-promoted cyclization to the spirodiketopiperazines, spiropyranose derivatives are produced in a complementary process. The central issue of this synthesis effort was the utilization of 4-phenylseleno-substituted furanoid glycals so as to ultimately enable introduction of the cis-diol functionality at C-3 and C-4 (hydantocidin numbering).

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Section: Resultsmentioning

confidence: 99%

An Enantioselective Ring Expansion Route Leading to Furanose and Pyranose Nucleosides Featuring Spirodiketopiperazines at the Anomeric Position

1999

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“…The difference in selectivity of additions of Grignard additions to a highly substituted cyclohexenone is striking (Scheme 193). 7 This enone is likely to adopt the conformation 497 that minimizes 1,2-allylic strain by placing the oxygen atoms equatorial (a similar enone adopts this type of conformation in the solid state 332 ). Whereas attack from the top face might be torsionally favored, it should be disfavored by a developing 1,3-diaxial interaction, whereas attack from the bottom face is more sterically accessible.…”

Section: Steric Approach Control and Stereoselectivitymentioning

confidence: 99%

Reactions of Allylmagnesium Reagents with Carbonyl Compounds and Compounds with C═N Double Bonds: Their Diastereoselectivities Generally Cannot Be Analyzed Using the Felkin–Anh and Chelation-Control Models

et al. 2020

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This review describes the additions of allylmagnesium reagents to carbonyl compounds and to imines, focusing on the differences in reactivity between allylmagnesium halides and other Grignard reagents. In many cases, allylmagnesium reagents either react with low stereoselectivity when other Grignard reagents react with high selectivity, or allylmagnesium reagents react with the opposite stereoselectivity. This review collects hundreds of examples, discusses the origins of stereoselectivities or the lack of stereoselectivity, and evaluates why selectivity may not occur and when it will likely occur. CONTENTS 4.2.5. Additions to β-Substituted Aldehydes 4.2.6. Additions to Aldehydes with Distant Chelating Groups 4.3. Additions to Cyclic Ketones 4.3.1. Alkoxy-Substituted Cyclic Ketones 4.3.2. Additions to Alkoxy-Substituted Five-Membered-Ring Ketones 4.3.3. Additions to Alkoxy-Substituted Four-Membered-Ring Ketones 4.4. Additions of Allylmagnesium Halides to Cyclic Hemiacetals 5. Diastereoselectivity of Reactions of Allylmagnesium Reagents with Carbonyl Compounds by Felkin−Anh Control 5.1. Felkin−Anh Stereoselectivity 5.2. Additions to α-Chiral Acyclic Ketones 5.3. Additions to Chiral Exocyclic Ketones and Aldehydes 5.4. Additions of Allylmagnesium Halides to Chiral Cyclic Ketones Controlled by Felkin−Anh Selectivity 5.5. Additions of Allylmagnesium Halides to Chiral Acyclic Aldehydes 6. Diastereoselectivity of Reactions with Carbonyl Compounds by Steric Approach Control 6.1. Steric Approach Control and Stereoselectivity

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“…1B). After the gel formation, two new absorption peaks appeared at 1659 and 1610 cm −1 due to the newly formed enamine double bonds in the gel network [33,35,36].…”

Section: Synthesis and Characterization Of Polymeric Gelsmentioning

confidence: 99%

Dynamic covalent cross-linked polymer gels through the reaction between side-chain β-keto ester and primary amine groups

Maiti

Ruidas

2015

Reactive and Functional Polymers

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trans,anti,trans-Tetra(spirotetrahydrofuranyl)cyclohexane-1,2-dione. Stereocontrolled Synthesis and Definition of Its Susceptibility to Photoisomerization

Cited by 14 publications

References 31 publications

An Enantioselective Ring Expansion Route Leading to Furanose and Pyranose Nucleosides Featuring Spirodiketopiperazines at the Anomeric Position

An Enantioselective Ring Expansion Route Leading to Furanose and Pyranose Nucleosides Featuring Spirodiketopiperazines at the Anomeric Position

Reactions of Allylmagnesium Reagents with Carbonyl Compounds and Compounds with C═N Double Bonds: Their Diastereoselectivities Generally Cannot Be Analyzed Using the Felkin–Anh and Chelation-Control Models

Dynamic covalent cross-linked polymer gels through the reaction between side-chain β-keto ester and primary amine groups

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