Topic
Annulation
About: Annulation is a research topic. Over the lifetime, 10152 publications have been published within this topic receiving 189701 citations.
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TL;DR: In this article, a system for in situ regeneration of SmI2 from SmI3 is described, which allows the annulation of ketones to γ-lactones, the deoxygenation of oxiranes to olefins and radical π-cyclization to be conducted with 10 mole % SmI 2.
67 citations
TL;DR: Indoles display a diverse pattern of reactivity upon reaction with different classes of aminobenzaldehydes as discussed by the authors, showing that the acid-promoted reaction with secondary amnobenzaldehyde leads to indole annulation followed by spontaneous oxidation to neocryptolepine and analogues.
Abstract: Indoles display a diverse pattern of reactivity upon reaction with different classes of aminobenzaldehydes. Whereas the acid-promoted reaction with secondary aminobenzaldehyde leads to indole annulation followed by spontaneous oxidation to neocryptolepine and analogues, the reaction with primary aminobenzaldehydes results in the formation of synthetically useful quinolinesvia a remarkably facile indole ring-opening.
67 citations
TL;DR: A highly convergent strategy involving the sequential annulation of vinyl iodide 5 with indole 6 exploits varying modes of indole reactivity to provide aspidophytine in 23% over six steps from 5.
Abstract: An expedient asymmetric total synthesis of aspidophytine is reported. A highly convergent strategy involving the sequential annulation of vinyl iodide 5 with indole 6 exploits varying modes of indole reactivity to provide aspidophytine in 23% over six steps from 5.
66 citations
TL;DR: The highly enantioselective NHC-catalyzed [3+2] annulation reaction with α,β-alkynals and α-ketoesters has been developed and a new mode of cooperative catalysis involving the combination of a chiral Brønsted acid and a C1-symmetric biaryl saturated-imidazolium precatalyst was required to generate the desired γ-crotonolactones.
Abstract: The highly enantioselective NHC-catalyzed [3+2] annulation reaction with α,β-alkynals and α-ketoesters has been developed. A new mode of cooperative catalysis involving the combination of a chiral Bronsted acid and a C1-symmetric biaryl saturated-imidazolium precatalyst was required to generate the desired γ-crotonolactones in high yields and levels of enantioselectivity.
66 citations
TL;DR: This process provides a direct method for the enantioselective construction of bi- or tricyclic dihydropyranopyrrolidin-2-one skeletons in only one step.
Abstract: Skeleton in the closet: The title reaction enables the development of the first catalytic β,γ-selective Diels-Alder [4+2] annulation of α,β-unsaturated γ-butyrolactams (see scheme; Boc=tert-butoxycarbonyl, Ts=4-toluenesulfonyl). This process provides a direct method for the enantioselective construction of bi- or tricyclic dihydropyranopyrrolidin-2-one skeletons in only one step.
66 citations