40 research outputs found

    Asymmetric Induction during Yang Cyclization of α-Oxoamides:  The Power of a Covalently Linked Chiral Auxiliary Is Enhanced in the Crystalline State

    No full text
    γ-Hydrogen abstraction has been revealed to be the primary photoprocess in the crystalline state of α-oxoamides through photochemical and X-ray structural studies. The outstanding ability of a covalent chiral auxiliary in generating asymmetric induction in the photoproduct β-lactam has been established with 10 examples. We have shown that the crystal lattice preorganizes the reactant molecules toward a single diastereomer of the β-lactam and prevents large motions of the 1,4-diradical intermediate that would result in the loss of stereochemical memory. A rare single-crystal-to-single-crystal transformation path of one of the examples investigated establishes the direct correlation between the stereochemistries of the reactant and the product

    Asymmetric Induction during Yang Cyclization of α-Oxoamides:  The Power of a Covalently Linked Chiral Auxiliary Is Enhanced in the Crystalline State

    No full text
    γ-Hydrogen abstraction has been revealed to be the primary photoprocess in the crystalline state of α-oxoamides through photochemical and X-ray structural studies. The outstanding ability of a covalent chiral auxiliary in generating asymmetric induction in the photoproduct β-lactam has been established with 10 examples. We have shown that the crystal lattice preorganizes the reactant molecules toward a single diastereomer of the β-lactam and prevents large motions of the 1,4-diradical intermediate that would result in the loss of stereochemical memory. A rare single-crystal-to-single-crystal transformation path of one of the examples investigated establishes the direct correlation between the stereochemistries of the reactant and the product

    Asymmetric Induction during Yang Cyclization of α-Oxoamides:  The Power of a Covalently Linked Chiral Auxiliary Is Enhanced in the Crystalline State

    No full text
    γ-Hydrogen abstraction has been revealed to be the primary photoprocess in the crystalline state of α-oxoamides through photochemical and X-ray structural studies. The outstanding ability of a covalent chiral auxiliary in generating asymmetric induction in the photoproduct β-lactam has been established with 10 examples. We have shown that the crystal lattice preorganizes the reactant molecules toward a single diastereomer of the β-lactam and prevents large motions of the 1,4-diradical intermediate that would result in the loss of stereochemical memory. A rare single-crystal-to-single-crystal transformation path of one of the examples investigated establishes the direct correlation between the stereochemistries of the reactant and the product

    Asymmetric Induction during Yang Cyclization of α-Oxoamides:  The Power of a Covalently Linked Chiral Auxiliary Is Enhanced in the Crystalline State

    No full text
    γ-Hydrogen abstraction has been revealed to be the primary photoprocess in the crystalline state of α-oxoamides through photochemical and X-ray structural studies. The outstanding ability of a covalent chiral auxiliary in generating asymmetric induction in the photoproduct β-lactam has been established with 10 examples. We have shown that the crystal lattice preorganizes the reactant molecules toward a single diastereomer of the β-lactam and prevents large motions of the 1,4-diradical intermediate that would result in the loss of stereochemical memory. A rare single-crystal-to-single-crystal transformation path of one of the examples investigated establishes the direct correlation between the stereochemistries of the reactant and the product

    Asymmetric Induction during Yang Cyclization of α-Oxoamides:  The Power of a Covalently Linked Chiral Auxiliary Is Enhanced in the Crystalline State

    No full text
    γ-Hydrogen abstraction has been revealed to be the primary photoprocess in the crystalline state of α-oxoamides through photochemical and X-ray structural studies. The outstanding ability of a covalent chiral auxiliary in generating asymmetric induction in the photoproduct β-lactam has been established with 10 examples. We have shown that the crystal lattice preorganizes the reactant molecules toward a single diastereomer of the β-lactam and prevents large motions of the 1,4-diradical intermediate that would result in the loss of stereochemical memory. A rare single-crystal-to-single-crystal transformation path of one of the examples investigated establishes the direct correlation between the stereochemistries of the reactant and the product

    Asymmetric Induction during Yang Cyclization of α-Oxoamides:  The Power of a Covalently Linked Chiral Auxiliary Is Enhanced in the Crystalline State

    No full text
    γ-Hydrogen abstraction has been revealed to be the primary photoprocess in the crystalline state of α-oxoamides through photochemical and X-ray structural studies. The outstanding ability of a covalent chiral auxiliary in generating asymmetric induction in the photoproduct β-lactam has been established with 10 examples. We have shown that the crystal lattice preorganizes the reactant molecules toward a single diastereomer of the β-lactam and prevents large motions of the 1,4-diradical intermediate that would result in the loss of stereochemical memory. A rare single-crystal-to-single-crystal transformation path of one of the examples investigated establishes the direct correlation between the stereochemistries of the reactant and the product

    Asymmetric Induction during Yang Cyclization of α-Oxoamides:  The Power of a Covalently Linked Chiral Auxiliary Is Enhanced in the Crystalline State

    No full text
    γ-Hydrogen abstraction has been revealed to be the primary photoprocess in the crystalline state of α-oxoamides through photochemical and X-ray structural studies. The outstanding ability of a covalent chiral auxiliary in generating asymmetric induction in the photoproduct β-lactam has been established with 10 examples. We have shown that the crystal lattice preorganizes the reactant molecules toward a single diastereomer of the β-lactam and prevents large motions of the 1,4-diradical intermediate that would result in the loss of stereochemical memory. A rare single-crystal-to-single-crystal transformation path of one of the examples investigated establishes the direct correlation between the stereochemistries of the reactant and the product

    Asymmetric Induction during Yang Cyclization of α-Oxoamides:  The Power of a Covalently Linked Chiral Auxiliary Is Enhanced in the Crystalline State

    No full text
    γ-Hydrogen abstraction has been revealed to be the primary photoprocess in the crystalline state of α-oxoamides through photochemical and X-ray structural studies. The outstanding ability of a covalent chiral auxiliary in generating asymmetric induction in the photoproduct β-lactam has been established with 10 examples. We have shown that the crystal lattice preorganizes the reactant molecules toward a single diastereomer of the β-lactam and prevents large motions of the 1,4-diradical intermediate that would result in the loss of stereochemical memory. A rare single-crystal-to-single-crystal transformation path of one of the examples investigated establishes the direct correlation between the stereochemistries of the reactant and the product

    Asymmetric Induction during Yang Cyclization of α-Oxoamides:  The Power of a Covalently Linked Chiral Auxiliary Is Enhanced in the Crystalline State

    No full text
    γ-Hydrogen abstraction has been revealed to be the primary photoprocess in the crystalline state of α-oxoamides through photochemical and X-ray structural studies. The outstanding ability of a covalent chiral auxiliary in generating asymmetric induction in the photoproduct β-lactam has been established with 10 examples. We have shown that the crystal lattice preorganizes the reactant molecules toward a single diastereomer of the β-lactam and prevents large motions of the 1,4-diradical intermediate that would result in the loss of stereochemical memory. A rare single-crystal-to-single-crystal transformation path of one of the examples investigated establishes the direct correlation between the stereochemistries of the reactant and the product

    Viability of a Covalent Chiral Auxiliary Method to Induce Asymmetric Induction in Solid-State Photoreactions Explored

    No full text
    The effectiveness of covalent chiral auxiliaries in inducing stereoselectivity during the Yang type II photocyclization reaction was examined using the benzonorbornene phenyl ketone (2) and α-adamantylacetophenone (7) systems. The outstanding ability of covalent chiral auxiliaries in generating high asymmetric induction in the photoproducts has been established in 7 of the 10 investigated examples. Three examples in which molecules crystallize with equal amounts of conformational isomers in the asymmetric unit, despite the covalently linked chiral auxiliary, highlight the limits of the use of the covalent chiral auxiliary approach for asymmetric induction in the solid state
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