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Selective oxidative dehydrogenation of propane to propene using boron nitride catalysts

Stereodivergent Allylic Substitutions with Aryl Acetic Acid Esters by Synergistic Iridium and Lewis Base Catalysis - Journal of the American Chemical Society (ACS Publications)

Stereodivergent Allylic Substitutions with Aryl Acetic Acid Esters by Synergistic Iridium and Lewis Base Catalysis - Journal of the American Chemical Society (ACS Publications)
The preparation of all possible stereoisomers of a given chiral molecule bearing multiple stereocenters by a simple and unified method is a significant challenge in asymmetric catalysis. We report stereodivergent allylic substitutions with aryl acetic acid esters catalyzed synergistically by a metallacyclic iridium complex and benzotetramisole. 

Selective Metal‐free HB(C6F5)2 Catalyzed Allene Cyclotrimerization: Formation of 1,3,5‐Trimethylenecyclohexane and Its Tris‐hydroboration Product

Selective Metal‐free HB(C6F5)2 Catalyzed Allene Cyclotrimerization: Formation of 1,3,5‐Trimethylenecyclohexane and Its Tris‐hydroboration Product: Allene is cyclotrimerized under metal‐free conditions with the borane HB(C6F5)2 catalyst to selectively give 1,3,5‐trimethylenecyclohexane (3 a). Three‐fold hydroboration of the 1,3,5‐cyclotrimer with...

Asymmetric Strecker Reaction Arising from the Molecular Orientation of an Achiral Imine at the Single‐Crystal Face: Enantioenriched l‐ and d‐Amino Acids

Asymmetric Strecker Reaction Arising from the Molecular Orientation of an Achiral Imine at the Single‐Crystal Face: Enantioenriched l‐ and d‐Amino Acids: Strecker synthesis has long been considered one of the prebiotic reactions for the synthesis of α‐amino acids. However, the correlation between the origin of chirality and highly enantioenriched α‐amino...

Development and Cycloaddition Reactivity of a New Class of Pyridine‐Based Mesoionic 1,3‐Dipole

Development and Cycloaddition Reactivity of a New Class of Pyridine‐Based Mesoionic 1,3‐Dipole: We describe here the development and structural characterization of a new type of mesoionic 1,3‐dipole, which can be generated in the one‐step reaction of imines with pyridine‐ or quinoline‐based acid...

N,B-Bidentate Boryl Ligand-Supported Iridium Catalyst for Efficient Functional-Group-Directed C–H Borylation - Journal of the American Chemical Society (ACS Publications)

N,B-Bidentate Boryl Ligand-Supported Iridium Catalyst for Efficient Functional-Group-Directed C–H Borylation - Journal of the American Chemical Society (ACS Publications)
Convenient silylborane precursors for introducing N,B-bidentate boryl ligands onto transition metals were designed, prepared, and employed in ready formation of irdium(III) complexes via Si–B oxidative addition. 

Diverse Visible‐Light‐Promoted Functionalizations of Benzotriazoles Inspired by Mechanism‐Based Luminescence Screening

Diverse Visible‐Light‐Promoted Functionalizations of Benzotriazoles Inspired by Mechanism‐Based Luminescence Screening: Three new visible‐light‐promoted functionalizations of benzotriazole substrates were discovered using a mechanism‐based screening method. ortho‐Thiolated, borylated, and alkylated N‐arylbenzamide products...

A Conia‐Ene‐Type Cyclization under Basic Conditions Enables an Efficient Synthesis of (−)‐Lycoposerramine R

A Conia‐Ene‐Type Cyclization under Basic Conditions Enables an Efficient Synthesis of (−)‐Lycoposerramine R: An enantioselective total synthesis of the Lycopodium alkaloid lycoposerramine R is presented. It relies on a base‐mediated cyclization that resembles the Conia‐ene reaction of ynones and gold‐catalyzed...

Oxidative Intramolecular 1,2‐Amino‐Oxygenation of Alkynes under AuI/AuIII‐Catalysis: Discovery of Pyridinium‐Oxazole Dyad as an Ionic Fluorophore

Oxidative Intramolecular 1,2‐Amino‐Oxygenation of Alkynes under AuI/AuIII‐Catalysis: Discovery of Pyridinium‐Oxazole Dyad as an Ionic Fluorophore: Oxidative intramolecular 1,2‐amino‐oxygenation reactions, combining gold(I)/gold(III) catalysis, is reported. The reaction provides efficient access to a structurally unique ionic pyridinium‐oxazole dyad...

Catalytic Enantioselective Arylboration of Alkenylarenes

Catalytic Enantioselective Arylboration of Alkenylarenes: A method for the catalytic enantioselective arylboration of alkenylarenes is disclosed. The reaction leads to the formation of 1,1‐diarylalkanes that also incorporate an additional pinacol boronic ester...

One‐Step Annulative π‐Extension of Alkynes with Dibenzosiloles or Dibenzogermoles by Palladium/o‐chloranil Catalysis

One‐Step Annulative π‐Extension of Alkynes with Dibenzosiloles or Dibenzogermoles by Palladium/o‐chloranil Catalysis: Reliable and short synthetic routes to polycyclic aromatic hydrocarbons and nanographenes are important in materials science. Herein, we report an efficient one‐step annulative π‐extension reaction of...

Radical Desulfur‐Fragmentation and Reconstruction of Enol Triflates: Facile Access to α‐Trifluoromethyl Ketones

Radical Desulfur‐Fragmentation and Reconstruction of Enol Triflates: Facile Access to α‐Trifluoromethyl Ketones: We report an efficient oxidative radical desulfur‐fragmentation and reconstruction of enol triflates for the synthesis of α‐CF3 ketones. Preliminary mechanistic studies disclosed that oxidative fragmentation...

Combination of Cp*RhIII‐Catalyzed C−H Activation and a Wagner–Meerwein‐Type Rearrangement

Combination of Cp*RhIII‐Catalyzed C−H Activation and a Wagner–Meerwein‐Type Rearrangement: A combination of Cp*RhIII‐catalyzed C−H activation and Wagner–Meerwein‐type rearrangement was successfully achieved for the first time. Thus, bridged polycyclic molecules that are not readily accessible...

Gold‐Catalyzed Direct Oxidative Arylation with Boron Coupling Partners

Gold‐Catalyzed Direct Oxidative Arylation with Boron Coupling Partners: An efficient synthesis of biaryls through a gold‐catalyzed oxidative cross‐coupling of arenes with strong electron‐deprived aryl boronates is presented herein. Regio‐ and chemocontrol are achieved by the...

Pyridine-Catalyzed Radical Borylation of Aryl Halides - Journal of the American Chemical Society (ACS Publications)

Pyridine-Catalyzed Radical Borylation of Aryl Halides - Journal of the American Chemical Society (ACS Publications)
A pyridine-catalyzed transition-metal-free borylation reaction of haloarenes has been developed based on the selective cross-coupling of an aryl radical and a pyridine-stabilized boryl radical. Arylboronates were produced from haloarenes under mild conditions. 

Versatile Homoallylic Boronates by Chemo‐, SN2′‐, Diastereo‐ and Enantioselective Catalytic Sequence of Cu−H Addition to Vinyl‐B(pin)/Allylic Substitution

Versatile Homoallylic Boronates by Chemo‐, SN2′‐, Diastereo‐ and Enantioselective Catalytic Sequence of Cu−H Addition to Vinyl‐B(pin)/Allylic Substitution: A highly chemo‐, diastereo‐ and enantioselective catalytic method that efficiently combines a silyl hydride, vinyl‐B(pin) (pin=pinacolato) and (E)‐1,2‐disubstituted allylic phosphates is introduced. Reactions,...

Palladium‐Catalyzed Asymmetric Allylic Allylation of Racemic Morita–Baylis–Hillman Adducts

Palladium‐Catalyzed Asymmetric Allylic Allylation of Racemic Morita–Baylis–Hillman Adducts: A palladium‐catalyzed asymmetric allyl–allyl cross‐coupling of acetates of racemic Morita–Baylis–Hillman adducts and allylB(pin) has been developed using a spiroketal‐based bis(phosphine) as the chiral...

Copper/P(tBu)3‐Mediated Regiospecific Synthesis of Fused Furans and Naphthofurans

Copper/P(tBu)3‐Mediated Regiospecific Synthesis of Fused Furans and Naphthofurans: A novel [3+2] cycloaddition between a variety of cyclic ketones and diverse olefins or alkynes can be effectively promoted by copper in combination with the tri‐tert‐butylphosphine [P(tBu)3] ligand. This...

Gold(I)/Chiral N,N′‐Dioxide–Nickel(II) Relay Catalysis for Asymmetric Tandem Intermolecular Hydroalkoxylation/Claisen Rearrangement

Gold(I)/Chiral N,N′‐Dioxide–Nickel(II) Relay Catalysis for Asymmetric Tandem Intermolecular Hydroalkoxylation/Claisen Rearrangement: A highly efficient asymmetric cascade reaction between alkynyl esters and allylic alcohols has been realized. Key to success was the combination of a hydroalkoxylation reaction catalyzed by a π‐acidic...

Photoarylation of Iodocarboranes with Unactivated (Hetero)Arenes: Facile Synthesis of 1,2‐[(Hetero)Aryl]n‐o‐Carboranes (n=1,2) and o‐Carborane‐Fused Cyclics

Photoarylation of Iodocarboranes with Unactivated (Hetero)Arenes: Facile Synthesis of 1,2‐[(Hetero)Aryl]n‐o‐Carboranes (n=1,2) and o‐Carborane‐Fused Cyclics: Photoarylation of iodocarboranes with unactivated arenes/heteroarenes at room temperature has been achieved, for the first time, thus leading to the facile synthesis of a large variety of cage carbon mono(hetero)arylated...

Enantioselective Synthesis and Racemization of (−)‐Sinoracutine

Enantioselective Synthesis and Racemization of (−)‐Sinoracutine: Sinoracutine is a recently isolated alkaloid with unusual stereochemical and biological properties. It features an unprecedented tetracyclic 6/6/5/5 skeleton that bears an N‐methylpyrrolidine ring fused...

Construction of Chiral Tetraorganosilicons by Tandem Desymmetrization of Silacyclobutanes/Intermolecular Dehydrogenative Silylation

Construction of Chiral Tetraorganosilicons by Tandem Desymmetrization of Silacyclobutanes/Intermolecular Dehydrogenative Silylation: We report a method to construct chiral tetraorganosilicons by tandem silacyclobutane (SCB) desymmetrization–dehydrogenative silylations. A wide array of dibenzosiloles with stereogenic quaternary silicon...

Buttressing Salicylaldehydes: Multipurpose Directing Group for C(sp3)−H Bond Activation

Buttressing Salicylaldehydes: Multipurpose Directing Group for C(sp3)−H Bond Activation: A palladium‐catalyzed reaction of primary amines with iodoarenes produces γ‐arylated primary amines. A bulky salicylaldehyde, which is marked as easily available, installable, removable, and recoverable,...

Total Synthesis of (−)‐Histrionicotoxin through a Stereoselective Radical Translocation–Cyclization Reaction

Total Synthesis of (−)‐Histrionicotoxin through a Stereoselective Radical Translocation–Cyclization Reaction: Stereoselective total syntheses of (−)‐histrionicotoxin and (−)‐histrionicotoxin 235A are described. The 1‐azaspiro[5.5]undecane skeleton was constructed diastereoselectively by a radical translocation–cyclization...

Photocatalytic Dehydrogenative Cross‐Coupling of Alkenes with Alcohols or Azoles without External Oxidant

Photocatalytic Dehydrogenative Cross‐Coupling of Alkenes with Alcohols or Azoles without External Oxidant: Direct cross‐coupling between alkenes/R‐H or alkenes/RXH is a dream reaction, especially without external oxidants. Inputting energy by photocatalysis and employing a cobalt catalyst as a two‐electron...

Oxidative Entry into the Illicium Sesquiterpenes: Enantiospecific Synthesis of ( )-Pseudoanisatin - Journal of the American Chemical Society (ACS Publications)

Oxidative Entry into the Illicium Sesquiterpenes: Enantiospecific Synthesis of ( )-Pseudoanisatin - Journal of the American Chemical Society (ACS Publications)
Illicium sesquiterpenes have been the subject of numerous synthetic efforts due to their ornate and highly oxidized structures as well as significant biological activities. Herein we report the first chemical synthesis of (+)-pseudoanisatin from the abundant feedstock chemical cedrol (∼$50 USD/kg) in 12 steps using extensive site-selective C(sp3)–H bond functionalization. 

Stereospecific Palladium‐Catalyzed Acylation of Enantioenriched Alkylcarbastannatranes: A General Alternative to Asymmetric Enolate Reactions

Stereospecific Palladium‐Catalyzed Acylation of Enantioenriched Alkylcarbastannatranes: A General Alternative to Asymmetric Enolate Reactions: We report the development of a Pd‐catalyzed process for the cross coupling of unactivated primary, secondary, and tertiary alkylcarbastannatrane nucleophiles with acyl electrophiles. Reactions involving...

Nickel‐Catalyzed Barton Decarboxylation and Giese Reactions: A Practical Take on Classic Transforms

Nickel‐Catalyzed Barton Decarboxylation and Giese Reactions: A Practical Take on Classic Transforms: Two named reactions of fundamental importance and paramount utility in organic synthesis have been reinvestigated, the Barton decarboxylation and Giese radical conjugate addition. N‐hydroxyphthalimide...

Development of Gold‐catalyzed [4 1] and [2 2 1]/[4 2] Annulations between Propiolate Derivatives and Isoxazoles

Development of Gold‐catalyzed [4 1] and [2 2 1]/[4 2] Annulations between Propiolate Derivatives and Isoxazoles: Two new gold‐catalyzed annulations of isoxazoles with propiolates have been developed. Most isoxazoles follow an initial O attack on the alkyne to afford a [4+1] annulation product. This process results...

Catalysis with Chalcogen Bonds

Catalysis with Chalcogen Bonds: Herein, we introduce catalysts that operate with chalcogen bonds. Compared to conventional hydrogen bonds, chalcogen bonds are similar in strength but more directional and hydrophobic, thus ideal for precision...

A Stereoconvergent Cyclopropanation Reaction of Styrenes

A Stereoconvergent Cyclopropanation Reaction of Styrenes: The first stereoconvergent cyclopropanation reaction by means of photoredox catalysis using diiodomethane as the methylene source is described. This transformation exhibits broad functional group tolerance...

A Robust and Broadly Applicable Cobalt‐Catalyzed Cross‐Coupling of Functionalized Bench‐Stable Organozinc Pivalates with Unsaturated Halides

A Robust and Broadly Applicable Cobalt‐Catalyzed Cross‐Coupling of Functionalized Bench‐Stable Organozinc Pivalates with Unsaturated Halides: We report a robust and broadly applicable CoCl2‐catalyzed cross‐coupling between functionalized aryl and heteroaryl zinc pivalates and various electron‐poor aryl and heteroaryl halides (X=Cl, Br, I). Couplings...

Chemoselective Suzuki–Miyaura Cross‐Coupling via Kinetic Transmetallation

Chemoselective Suzuki–Miyaura Cross‐Coupling via Kinetic Transmetallation: Chemoselective Suzuki–Miyaura cross‐coupling generally requires a designed deactivation of one nucleophile towards transmetallation. Here we show that boronic acids can be chemoselectively reacted in the...

Enantioselective photochemistry through Lewis acid–catalyzed triplet energy transfer

A Chiral Nitrogen Ligand for Enantioselective, Iridium‐Catalyzed Silylation of Aromatic C−H Bonds

A Chiral Nitrogen Ligand for Enantioselective, Iridium‐Catalyzed Silylation of Aromatic C−H Bonds: Iridium catalysts containing dative nitrogen ligands are highly active for the borylation and silylation of C−H bonds, but chiral analogs of these catalysts for enantioselective silylation reactions have...

α‐Arylation and Ring Expansion of Annulated Cyclobutanones: Stereoselective Synthesis of Functionalized Tetralones

α‐Arylation and Ring Expansion of Annulated Cyclobutanones: Stereoselective Synthesis of Functionalized Tetralones: α‐Arylcyclobutanones display unique reactivity that makes them valuable synthetic intermediates and target molecules. We describe the preparation of α‐aryl‐ and α‐heteroarylcyclobutanones through a direct...

Rhodium(I)‐Catalyzed Intermolecular Aza‐[4 3] Cycloaddition of Vinyl Aziridines and Dienes: Atom‐Economical Synthesis of Enantiomerically Enriched Functionalized Azepines

Rhodium(I)‐Catalyzed Intermolecular Aza‐[4 3] Cycloaddition of Vinyl Aziridines and Dienes: Atom‐Economical Synthesis of Enantiomerically Enriched Functionalized Azepines: A new synthetic application of vinyl aziridines as N‐containing three‐atom components in a rhodium‐catalyzed [4+3] cycloaddition reaction is described. The reaction proceeds well with various silyl dienol...

Hypervalent Iodine(III)‐Mediated Oxidative Fluorination of Alkylsilanes by Fluoride Ions

Hypervalent Iodine(III)‐Mediated Oxidative Fluorination of Alkylsilanes by Fluoride Ions: The first example of a hypervalent iodine(III)‐mediated oxidative fluorination of alkylsilanes by fluoride ions without the use of transition metals is demonstrated. This reaction is operationally simple,...

A Four‐Component Reaction Strategy for Pyrimidine Carboxamide Synthesis

A Four‐Component Reaction Strategy for Pyrimidine Carboxamide Synthesis: Demonstrated herein is a highly effective 3 starting materials–4 component reaction (3SM‐4CR) strategy for the synthesis of pyrimidine carboxamides from amidines, styrene, and N,N‐dimethylformamide (DMF)...

Benzo‐Fused Double [7]Carbohelicene: Synthesis, Structures, and Physicochemical Properties

Benzo‐Fused Double [7]Carbohelicene: Synthesis, Structures, and Physicochemical Properties: A benzo‐fused double [7]carbohelicene (D7H) was synthesized through a regioselective cyclodehydrogenation of a tetranaphthyl‐p‐terphenyl‐based precursor. The twisted (D7H‐1) and anti‐folded (D7H‐2) conformers...

Regioselective Thiocarbonylation of Vinyl Arenes - Journal of the American Chemical Society (ACS Publications)

Regioselective Thiocarbonylation of Vinyl Arenes - Journal of the American Chemical Society (ACS Publications)
A palladium-catalyzed thiocarbonylation of styrene derivatives is reported for the first time. The combination of thiols as nucleophiles and a bidentate ligand ensures a unique reaction outcome with high regioselectivity toward the more valuable branched isomer and new reactivity.
 

Copper Catalyzed sp3 C–H Etherification with Acyl Protected Phenols - Journal of the American Chemical Society (ACS Publications)

Copper Catalyzed sp3 C–H Etherification with Acyl Protected Phenols - Journal of the American Chemical Society (ACS Publications)
A variety of acyl protected phenols AcOAr participate in sp3 C-H etherification of substrates R-H to give alkyl aryl ethers R-OAr employing tBuOOtBu as oxidant with copper(I) β-diketiminato catalysts [CuI]. Although 1°, 2°, and 3° C-H bonds may be functionalized, selectivity studies reveal a preference for the construction of hindered, 3° C-OAr bonds.
 

Stereodivergent Olefination of Enantioenriched Boronic Esters

Stereodivergent Olefination of Enantioenriched Boronic Esters: A stereodivergent coupling reaction between vinyl halides and boronic esters is described. This coupling process proceeds without a transition‐metal catalyst, instead proceeding by electrophilic selenation...

Palladium-Catalyzed Asymmetric α-Arylation of Alkylnitriles - Journal of the American Chemical Society (ACS Publications)

Palladium-Catalyzed Asymmetric α-Arylation of Alkylnitriles - Journal of the American Chemical Society (ACS Publications)
Asymmetric arylation of alkylnitriles forms quaternary stereocenters in good enantiocontrol for the first time. A lithium heterodimer consisting of an alkylnitrile anion and a disilylamide ion is the actual species responsible for the stereodetermining transmetalation in the catalytic cycle.
 

Extension of Pd-Mediated One-Pot Ketone Synthesis to Macrocyclization: Application to a New Convergent Synthesis of Eribulin - Journal of the American Chemical Society (ACS Publications)

Extension of Pd-Mediated One-Pot Ketone Synthesis to Macrocyclization: Application to a New Convergent Synthesis of Eribulin - Journal of the American Chemical Society (ACS Publications)
A new convergent synthesis of eribulin has been achieved, using (1) catalytic asymmetric Ni/Cr-mediated coupling to form the C19–C20 bond, (2) base-induced cyclization to form the methylenetetrahydrofuran ring, and (3) Pd-mediated one-pot ketone synthesis to form the macrocyclic ketone.
 

Diols, α-Ketols, and Diones as 22π Components in [2 2 2] Cycloadditions of 1,6-Diynes via Ruthenium(0)-Catalyzed Transfer Hydrogenation - Journal of the American Chemical Society (ACS Publications)

Diols, α-Ketols, and Diones as 22π Components in [2 2 2] Cycloadditions of 1,6-Diynes via Ruthenium(0)-Catalyzed Transfer Hydrogenation - Journal of the American Chemical Society (ACS Publications)
The first use of vicinal diols, ketols, or diones as 2 components in metal-catalyzed [2+2+2] cycloaddition is described. Using ruthenium(0) catalysts, 1,6-diynes form ruthenacyclopentadienes that engage transient diones in successive carbonyl addition. 

Phosphoric Acid-Catalyzed Asymmetric Synthesis of SPINOL Derivatives - Journal of the American Chemical Society (ACS Publications)

Phosphoric Acid-Catalyzed Asymmetric Synthesis of SPINOL Derivatives - Journal of the American Chemical Society (ACS Publications)
Axially chiral 1,1′-spirobiindane-7,7′-diol (SPINOL) is the most fundamental and important privileged structure from which other chiral ligands containing a 1,1′-spirobiindane backbone are synthesized. Driven by the development of enantioselective syntheses of axially chiral SPINOL derivatives, we have successfully developed the first phosphoric acid-catalyzed asymmetric approach.
 

Visible-Light-Promoted Activation of Unactivated C(sp3)–H Bonds and Their Selective Trifluoromethylthiolation - Journal of the American Chemical Society (ACS Publications)

Visible-Light-Promoted Activation of Unactivated C(sp3)–H Bonds and Their Selective Trifluoromethylthiolation - Journal of the American Chemical Society (ACS Publications)
Selective functionalization of ubiquitous C(sp3)–H bonds using visible light is a highly challenging yet desirable goal in organic synthesis. The development of such processes relies on both rational design and serendipitous discoveries from innovative tools such as screening technologies. Applying a mechanism-based screening strategy, we herein report photoredox-mediated hydrogen atom transfer catalysis for the selective activation of otherwise unactivated C(sp3)–H bonds, followed by their trifluoromethylthiolation, which has high potential as a late-stage functionalization tool.
 

Disulfide‐Catalyzed Visible‐Light‐Mediated Oxidative Cleavage of C=C Bonds and Evidence of an Olefin–Disulfide Charge‐Transfer Complex

Disulfide‐Catalyzed Visible‐Light‐Mediated Oxidative Cleavage of C=C Bonds and Evidence of an Olefin–Disulfide Charge‐Transfer Complex: A photocatalytic method for the aerobic oxidative cleavage of C=C bonds has been developed. Electron‐rich aromatic disulfides were employed as photocatalyst. Upon visible‐light irradiation, typical mono‐...

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