Desymmetrization of Cyclohexadienones Containing a Quaternary γ-Carbon Atom by Conjugate Addition of Boron Nucleophiles

ACS Catalysis, Год журнала: 2023, Номер 14(1), С. 176 - 182

Опубликована: Дек. 12, 2023

A highly enantio- and diastereoselective copper-catalyzed conjugate monoborylation of γ,γ-disubstituted cyclohexadienone derivatives is reported. Two contiguous stereocenters are generated in this group-selective reaction, one at the formed boron-bearing carbon atom a neopentylic position quaternary atom. subsequent 1,4-addition boron nucleophile to remaining α,β-unsaturated acceptor allows for construction another stereocenter other position, thereby leading three adjacent stereogenic atoms congested environment. The diastereoselectivity that second borylation can be controlled by different chiral ligands selectively afford either syn- or anti-1,3-diborylated product.

Язык: Английский

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PolyBorylated Alkenes as Energy‐Transfer Reactive Groups: Access to Multi‐Borylated Cyclobutanes Combined with Hydrogen Atom Transfer Event

Angewandte Chemie, Год журнала: 2024, Номер 136(25)

Опубликована: Апрель 11, 2024

Abstract While polyborylated alkenes are being recognized for their elevated status as highly valuable reagents in modern organic synthesis, allowing efficient access to a diverse array of transformations, including the formation C−C and C‐heteroatom bonds, potential energy‐transfer reactive groups has remained unexplored. Yet, this holds key generating elusive biradical species, which can be captured by olefins, thereby leading construction new highly‐borylated scaffolds. Herein, we report designed strategy photosensitized [2+2]‐cycloadditions poly‐borylated with various olefins enabling regioselective synthesis cyclobutane motifs, 1,1‐di‐, 1,1,2‐tri‐, 1,1,2,2‐tetra‐borylated cyclobutanes. In fact, these compounds belong family that presently lacks synthetic pathways. Interestingly, when α‐methylstyrene was used, reaction involves an interesting 1,5‐hydrogen atom transfer (HAT). Mechanistic deuterium‐labeling studies have provided insight into outcome process. addition, cyclobutanes then demonstrated useful selective oxidation processes resulting cyclobutanones γ‐lactones.

Язык: Английский

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Tandem Diboration–Protoboration of Terminal Alkynes: A Practical Route to α-Substituted Alkenyl Boronates

Synlett, Год журнала: 2024, Номер unknown

Опубликована: Июнь 5, 2024

Abstract A practical method is introduced for the catalytic conversion of terminal alkynes into α-substituted vinyl boronic esters. The process employs amounts nanoparticle-supported gold catalysts and copper to effect overall transformation.

Язык: Английский

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Stereoselective C−B and C−H Bonds Functionalization of PolyBorylated Alkenes

Angewandte Chemie International Edition, Год журнала: 2024, Номер 63(45)

Опубликована: Июль 9, 2024

Abstract Alkenes are fundamental functional groups which feature in various materials and bioactive molecules; however, efficient divergent strategies for their stereodefined synthesis difficult. In this regard, numerous synthetic methodologies have been developed to construct carbon–carbon bonds with regio‐ stereoselectivity, enabling the predictable of alkenes. fact, an appealing alternative approach accessing challenging alkene molecular frameworks could involve sequential selective activation cross‐coupling strong instead conventional C−C bond formation. study, we introduce a series programmed site‐ stereoselective that capitalizes on versatile reactivity readily accessible polymetalloid alkenes (i.e. polyborylated alkenes), through tandem reaction, is catalyzed by organometallic Rh‐complex produce complex scaffolds. By merging C−B remote C−H functionalization, achieve situ generation polyfunctional C(sp 2 )‐nucleophilic intermediates. These species can be further modified coupling reactions C‐based electrophiles, formation )−C(sp 3 ) even more architectures using available starting polyborylated‐alkenes. Mechanistic computational studies provide insight into origins stereoselectivities via 1,4‐Rh migration process.

Язык: Английский

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Gold/HNTf₂-Cocatalyzed Asymmetric Annulation of Diazo-Alkynes: Divergent Construction of Atropisomeric Biaryls and Arylquinones

Journal of the American Chemical Society, Год журнала: 2024, Номер unknown

Опубликована: Ноя. 30, 2024

Due to the inherent challenges posed by linear coordination of gold(I) complexes, asymmetric gold-catalyzed processes remain challenging, particularly in atroposelective synthesis axially chiral skeletons. Except for extremely few examples intramolecular annulations, construction axial chirality via intermolecular alkyne transformation is still undeveloped. Herein, a gold/HNTf

Язык: Английский

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