منابع مشابه
Ni(NHC)]-Catalyzed Cycloaddition of Diynes and Tropone: Apparent Enone Cycloaddition Involving an 8π Insertion
A Ni/N-heterocyclic carbene catalyst couples diynes to the C(α)-C(β) double bond of tropone, a type of reaction that is unprecedented for metal-catalyzed cycloadditions with aromatic tropone. Many different diynes were efficiently coupled to afford [5-6-7] fused tricyclic products, while [5-7-6] fused tricyclic compounds were obtained as minor byproducts in a few cases. The reaction has broad s...
متن کاملRapid cycloaddition of a diazo group with an unstrained dipolarophile.
The cycloaddition of a diazoacetamide with ethyl 4,4,4-trifluorocrotonate proceeds with k = 0.1 M-1s-1. This second-order rate constant rivals those of optimized strain-promoted azide- alkyne cycloadditions, even though the reaction does not release strain. The regioselectivity and a computational distortion/interaction analysis of the reaction energetics are consistent with the formation of an...
متن کاملComputational Insights into an Enzyme-Catalyzed [4+2] Cycloaddition
The enzyme SpnF, involved in the biosynthesis of spinosyn A, catalyzes a formal [4+2] cycloaddition of a 22-membered macrolactone, which may proceed as a concerted [4+2] Diels-Alder reaction or a stepwise [6+4] cycloaddition followed by a Cope rearrangement. Quantum mechanics/molecular mechanics (QM/MM) calculations combined with free energy simulations show that the Diels-Alder pathway is favo...
متن کاملAn alkynylboronic ester cycloaddition route to functionalised aromatic boronic esters.
A series of functionalised aromatic boronic esters have been prepared via the regioselective cycloaddition of 2-pyrones with alkynylboronates.
متن کاملFormal [2 + 2 + 2] cycloaddition strategy based on an intramolecular propargylic ene reaction/Diels-Alder cycloaddition cascade.
A formal, metal-free, [2 + 2 + 2] cycloaddition strategy is described based on a cascade of two pericyclic processes. The first step involves an intramolecular propargylic ene reaction of a 1,6-diyne to generate a vinylallene, which then reacts in an inter- or intramolecular Diels-Alder reaction with an alkenyl or alkynyl dienophile. Reactions involving unsymmetrical alkenyl and alkynyl dienoph...
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ژورنال
عنوان ژورنال: Angewandte Chemie
سال: 1973
ISSN: 0044-8249,1521-3757
DOI: 10.1002/ange.19730851511