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 Rh(III) -catalyzed reaction of O-methyl α,β-unsaturated oximes with aldehydes and N-tosyl imines affords secondary alcohol and amine intermediates, respectively.
Abstract: Ring in the new: a new annulation for the efficient synthesis of substituted furans and pyrroles is reported. The Rh(III) -catalyzed reaction of O-methyl α,β-unsaturated oximes with aldehydes and N-tosyl imines affords secondary alcohol and amine intermediates, respectively. Cyclization and aromatization occurs under the reaction conditions to provide access to biologically relevant furans and pyrroles in good yields. Cp*=C(5)Me(5), DCE=1,2-dichloroethane, THF=tetrahydrofuran.
161 citations
TL;DR: C-H/N-O functionalizations by cobalt(III) catalysis allowed the expedient synthesis of a broad range of isoquinolines and internal and challenging terminal alkynes proved to be viable substrates for an isohypsic annulation.
Abstract: C-H/N-O functionalizations by cobalt(III) catalysis allowed the expedient synthesis of a broad range of isoquinolines. Thus, internal and challenging terminal alkynes proved to be viable substrates for an isohypsic annulation, which was shown to proceed by a facile C-H cobaltation.
160 citations
TL;DR: A novel phosphine-catalyzed reaction of modified allylic compounds, including acetates, bromides, chlorides, or tert-butyl carbonates derived from the Morita-Baylis-Hillman (MBH) reaction with tropone to yield [3+6] annulation products in excellent yields was developed.
160 citations
TL;DR: A chemo- and enantioselective annulation of Morita-Baylis-Hillman carbonates of isatins with propargyl sulfones was catalyzed by a β-ICD O-MOM ether 1c, affording spirocyclic 2-oxindoles bearing an unusual cyclopentadiene motif in outstanding ee values.
160 citations
TL;DR: The first example of electrocatalytic C-H activation by weak O-coordination is presented, in which a versatile ruthenium(II) carboxylate catalyst enables electrooxidative C-h/O-H functionalization for alkyne annulations in the absence of metal oxidants.
Abstract: Electrocatalysis has been identified as a powerful strategy for organometallic catalysis, and yet electrocatalytic C-H activation is restricted to strongly N-coordinating directing groups. The first example of electrocatalytic C-H activation by weak O-coordination is presented, in which a versatile ruthenium(II) carboxylate catalyst enables electrooxidative C-H/O-H functionalization for alkyne annulations in the absence of metal oxidants; thereby exploiting sustainable electricity as the sole oxidant. Mechanistic insights provide strong support for a facile organometallic C-H ruthenation and an effective electrochemical reoxidation of the key ruthenium(0) intermediate.
160 citations