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: The main features of this reaction include challenging direct C(sp(3))-H bond functionalizations, excellent enantioselectivities, readily available starting materials, mild reaction conditions, high efficiency, and operational simplicity.
83 citations
TL;DR: The attractive feature of this approach is the synthesis of three important bioactive heterocyclic frameworks from the same β-oxodithioester under the similar reaction conditions, making this new strategy highly useful in diversity-oriented synthesis (DOS).
Abstract: An efficient and highly convergent route to dihydropyrimidinones (DHPMs) and hitherto unreported dihydropyridopyrimidinones has been developed by one-pot, three-component cyclocondensation of aromatic aldehydes, β-oxodithioesters, and urea/6-amino-1,3-dimethyluracil in the presence of recyclable SiO2-H2SO4. On the other hand, salicylaldehyde, β-oxodithioester, and urea reacted under similar conditions to afford the 3-aroyl/heteroaroyl-2H-chromen-2-thiones in high yields instead of Biginelli product. The attractive feature of this approach is the synthesis of three important bioactive heterocyclic frameworks from the same β-oxodithioester under the similar reaction conditions, making this new strategy highly useful in diversity-oriented synthesis (DOS).
83 citations
TL;DR: A novel axially chiral spiro-phosphine-catalyzed highly regio-, diastereo- and enantioselective [3+2] cycloaddition of alkylidene azlactones with various allenic esters has been developed, affording the corresponding functionalized spirocyclic products in moderate to excellent yields under mild conditions.
83 citations
TL;DR: Free-radical mediated stannylcarbonylation of azaenynes provides a general [n + 1]-type annulation approach leading to alpha-stannylmethylene lactams.
Abstract: Free-radical mediated stannylcarbonylation of azaenynes provides a general [n + 1]-type annulation approach leading to α-stannylmethylene lactams. The cyclization is unusual in its breadth, covering 4-exo, 5-exo, 6-exo, 7-exo, and 8-exo modes.
83 citations
TL;DR: A novel and facile route to functionalized mono/bicyclic 2,3-dihydro-4-pyridones has been developed via formal [5C + 1N] annulation of readily available alpha-alkenoyl ketene-(S,S)-acetals with various aliphatic primary amines.
82 citations