Triflic Acid-Catalyzed Additions of 2-Alkoxycarbonyl Allylboronates to Aldehydes. Study of Scope and Mechanistic Investigation of the Reaction Stereochemistry

Elford, Tim G.; Arimura, Yuichiro; Yu, Siu Hong; Hall, Dennis G.

doi:10.1021/jo062151b

Cited by 67 publications

(17 citation statements)

References 16 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…On the other hand, the analogous experiment with Brønsted acid catalysts resulted in a large rate enhancement. 91 The initially formed product 218 undergoes lactonization to 219 under the acid-catalyzed conditions. Although the mechanistic details remain uncertain, the borenium intermediate 217 was proposed as the species responsible for accelerating the reaction.…”

Section: Miscellaneous Applications Of Borenium Lewis Acidsmentioning

confidence: 99%

Cationic Tricoordinate Boron Intermediates: Borenium Chemistry from the Organic Perspective

2012

View full text Add to dashboard Cite

CONTENTS 1. Introduction 4246 2. History of Borenium Ions: Often Considered, Seldom Confirmed 4247 2.1. Suspected Intermediates in B−N Protonation 4247 2.2. Hypothetical Isomers of Cl 3 B•NHMe 2 4247 2.3. The First Observable Borenium Salt 4247 2.4. Nucleophilic Substitution of X 3 B•NR 3 and Py•BF 2 X 4248 2.5. Aminoborenium Ions, Stabilization by n-Delocalization 4249 3. Recent Developments in the Generation of Observable Borenium Intermediates 4249 3.1. Electrophilic Activation by Protonation or by Lewis Acid Catalysis 4249 3.2. Halide Abstraction by a Halophile 4250 3.3. The Borinium−Borenium Interface: Gas-Phase Oxyborenium Ions 4251 3.4. Borenium Salt Generation by Hydride Abstraction 4251 3 . 4 . 1 . H y d r i d e A b s t r a c t i o n b y T r i s -(pentafluorophenyl)borane 4251 3.4.2. Hydride Abstracton by Trityl Salts 4252 3.4.3. Hydride-Bridged Borenium Salt Dimers 4252 3.5. Borenium Ion Generation by Nucleophilic Addition−Heterolysis 4253 4. Borenium Lewis Acidity vs Structure 4254 4.1. Experimental Evaluation of Lewis Acidity 4254 4.2. Computational Evaluation of Borenium Lewis Acidity 4255 5. Borenium Ions and Stereogenic Boron 4257 5.1. Racemization by Heterolysis 4257 5.2. Asymmetric Memory at Stereogenic Boron 4257 5.3. Chiral Salicylaldimine Boronate Complexes 4258 6. Enantioselective Catalysis and Chiral Borenium Ions 4259 6.1. The Dual Function of Oxazaborolidines in the CBS Reduction 4260 6.2. The Role of Borenium Species in Diels−Alder Catalysis 4261 6.3. Reactivity and Scope of Oxazaborolidine-Derived Diels−Alder Catalysts 4263 6.4. Miscellaneous Uses of Chiral Borenium Lewis Acid Catalysts 4265 7. Miscellaneous Applications of Borenium Lewis Acids 4266 7.1. B−O Activation 4266 7.2. Lewis Acidity and π-Conjugated Borenium Analogues 4267 7.3. π-Conjugated Borenium Analogues as Selective Anion Sensors 4268 7.4. Tricoordinate Boron in Structures Containing Metal Cations 4269 8. Borenium Reagents for C−B Bond Formation 4269 8.1. Borenium Ion Equivalents 4269 8.2. Do Borenium Ions Participate in Hydroboration Chemistry? 4270 8.3. Borenium Equivalents in Electrophilic Aromatic Borylation 4271 8.3.1. Intramolecular Borylation 4271 8.3.2. Intermolecular Borylation 4272 8.3.3. Recent Developments in Muetterties Borylation (BX3 plus Proton Scavenger) 4275 9. Extension of Borenium Chemistry to Neighboring Fields and Unusual Environments 4276 9.1. N-Heterocyclic Carbenes as Stabilizing Ligands for Borenium Salts 4276 9.2. Miscellaneous Related Topics Involving BH Species 4277 10. Summary 4278 Author Information 4279 Corresponding Author 4279 Notes 4279 Biographies 4279 Acknowledgments 4279 References 4279

show abstract

Section: Miscellaneous Applications Of Borenium Lewis Acidsmentioning

confidence: 99%

Cationic Tricoordinate Boron Intermediates: Borenium Chemistry from the Organic Perspective

2012

View full text Add to dashboard Cite

show abstract

“…This method is limited to the preparation of g-alkyl derivatives, since g-aryl derivatives undergo a carbocation-mediated rearrangement to provide cis-or trans-b,g-disubstituted-a-methylene-g-butyrolactones. [83] A similar approach has been recently used by Chataigner and co-workers for the stereocontrolled synthesis of g-substituted-a-methylene-g-butyrolactones. [84] Subsequently, Ramachandran and co-workers extended their methodology to the synthesis of (Z)-a-alkylidene-g-arylg-butyrolactones 119 by alkenylalumination of the corresponding 2-aryloxirane 117.…”

Section: Lactonization Approachesmentioning

confidence: 99%

The Renaissance of α‐Methylene‐γ‐butyrolactones: New Synthetic Approaches

Kitson¹,

Millemaggi²,

Taylor³

2009

Angew Chem Int Ed

412

249

View full text Add to dashboard Cite

The amount of research activity concerning alpha-methylene-gamma-butyrolactones and alpha-alkylidene-gamma-butyrolactones has increased dramatically in recent years. This Review summarizes the structural types, biological activities, and biosynthesis of these compounds, concentrating on publications from the past 10 years. Traditional approaches to alpha-methylene-gamma-butyrolactones and alpha-alkylidene-gamma-butyrolactones are then reviewed together with novel approaches, including those from our own research group, reported more recently.

show abstract

“…[13] Protonation of the boronate oxygen by the catalyst was proposed to rationalize both the activation and the enantioselectivity. [14] The broadening of the limited scope of this type of activation is highly desired. Herein, we describe, to the best of our knowledge, the first example of highly enantioselective reduction of ketones catalyzed by a chiral phosphoric acid derivative.…”

mentioning

confidence: 99%

Asymmetric Reduction of Ketones by Phosphoric Acid Derived Catalysts

2011

View full text Add to dashboard Cite

A new path to chiral alcohols: Asymmetric reduction of ketones was achieved utilizing a chiral Brønsted acid as precatalyst for the first time. Using catecholborane as the reducing agent, a highly enantioselective formation of chiral secondary alcohols was found with a broad substrate scope. Mechanistic studies indicate that phosphoryl catechol borate derived from the reaction of the Brønsted acid with catecholborane produced the active catalyst (see scheme).

show abstract

Triflic Acid-Catalyzed Additions of 2-Alkoxycarbonyl Allylboronates to Aldehydes. Study of Scope and Mechanistic Investigation of the Reaction Stereochemistry

Cited by 67 publications

References 16 publications

Cationic Tricoordinate Boron Intermediates: Borenium Chemistry from the Organic Perspective

Cationic Tricoordinate Boron Intermediates: Borenium Chemistry from the Organic Perspective

The Renaissance of α‐Methylene‐γ‐butyrolactones: New Synthetic Approaches

Asymmetric Reduction of Ketones by Phosphoric Acid Derived Catalysts

Contact Info

Product

Resources

About