Practical Intermolecular Hydroarylation of Terminal Alkenes via Reductive Heck Coupling

The hydroarylation of alkenes is an attractive approach to construct carbon–carbon (C–C) bonds from abundant and structurally diverse starting materials. Herein we report a palladium-catalyzed reductive Heck hydroarylation of unactivated and heteroatom-substituted terminal alkenes with an array of (hetero)aryl iodides. The reaction is anti-Markovnikov selective and tolerates a wide variety of functional groups on both the alkene and (hetero)aryl coupling partners. Additionally, applications of this method to complex molecule diversifications were demonstrated. Deuterium-labeling experiments are consistent with a mechanism in which the key alkylpalladium(II) intermediate is intercepted with formate and undergoes a decarboxylation/C–H reductive elimination cascade to afford the saturated product and turn over the cycle. <br

Palladium(II)-Catalyzed Regioselective syn-Hydroarylation of Disubstituted Alkynes Using a Removable Directing Group

A palladium­(II)-catalyzed regioselective <i>syn</i>-hydroarylation reaction of homopropargyl amines has been developed, wherein selectivity is controlled by a cleavable bidentate directing group. Under the optimized reaction conditions, both dialkyl and alkylaryl alkyne substrates were found to undergo hydroarylation with high selectivity. The products of this reaction contain a 4,4-disubstituted homoallylic amine motif that is commonly seen in drug molecules and other bioactive compounds

Catalytic Carbo- and Aminoboration of Alkenyl Carbonyl Compounds via Five- and Six-Membered Palladacycles

A palladium­(II)-catalyzed alkene difunctionalization reaction has been developed, wherein B₂pin₂ is used to trap chelation-stabilized alkylpalladium­(II) intermediates that are formed upon nucleopalladation. A range of carbon and nitrogen nucleophiles were found to be suitable coupling partners in this transformation, providing moderate to high yields. Both 3-butenoic and 4-pentenoic acid derivatives were reactive substrate classes, affording β,γ- and γ,δ-difunctionalized carboxylic acid derivatives. This work represents a new strategy to synthesize highly functionalized secondary boronates that complements existing methods

Catalytic Carbo- and Aminoboration of Alkenyl Carbonyl Compounds via Five- and Six-Membered Palladacycles

A palladium­(II)-catalyzed alkene difunctionalization reaction has been developed, wherein B₂pin₂ is used to trap chelation-stabilized alkylpalladium­(II) intermediates that are formed upon nucleopalladation. A range of carbon and nitrogen nucleophiles were found to be suitable coupling partners in this transformation, providing moderate to high yields. Both 3-butenoic and 4-pentenoic acid derivatives were reactive substrate classes, affording β,γ- and γ,δ-difunctionalized carboxylic acid derivatives. This work represents a new strategy to synthesize highly functionalized secondary boronates that complements existing methods

β,γ-Vicinal Dicarbofunctionalization of Alkenyl Carbonyl Compounds via Directed Nucleopalladation

A palladium­(II)-catalyzed 1,2-dicarbofunctionalization reaction of unactivated alkenes has been developed, wherein a cleavable bidentate directing group is used to control the regioselectivity and stabilize the putative alkylpalladium­(II) intermediate. Under the optimized reaction conditions, a broad range of nucleophiles and electrophiles were found to participate in this transformation, providing moderate to high yields. 3-Butenoic acid derivatives containing internal alkenes and α-substituents were reactive substrates, offering a powerful platform for preparing β,γ-substituted carbonyl compounds with multiple stereocenters

Catalytic Carbo- and Aminoboration of Alkenyl Carbonyl Compounds via Five- and Six-Membered Palladacycles

A palladium­(II)-catalyzed alkene difunctionalization reaction has been developed, wherein B₂pin₂ is used to trap chelation-stabilized alkylpalladium­(II) intermediates that are formed upon nucleopalladation. A range of carbon and nitrogen nucleophiles were found to be suitable coupling partners in this transformation, providing moderate to high yields. Both 3-butenoic and 4-pentenoic acid derivatives were reactive substrate classes, affording β,γ- and γ,δ-difunctionalized carboxylic acid derivatives. This work represents a new strategy to synthesize highly functionalized secondary boronates that complements existing methods

Catalytic, Regioselective Hydrocarbofunctionalization of Unactivated Alkenes with Diverse C–H Nucleophiles

Reactions that forge carbon–carbon (C–C) bonds are the bedrock of organic synthesis, widely used across the chemical sciences. We report a transformation that enables C–C bonds to be constructed from two classes of commonly available starting materials, alkenes and carbon–hydrogen (C–H) bonds. The reaction employs a palladium­(II) catalyst and utilizes a removable directing group to both control the regioselectivity of carbopalladation and enable subsequent protodepalladation. A wide range of alkenes and C–H nucleophiles, including 1,3-dicarbonyls, aryl carbonyls, and electron-rich aromatics, are viable reaction partners, allowing Michael-type reactivity to be expanded beyond α,β-unsaturated carbonyl compounds to unactivated alkenes. Applications of this transformation in drug diversification and natural product total synthesis are described. Stoichiometric studies support each of the proposed steps in the catalytic cycle

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