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: On the basis of the reactions of camphor-derived sulfur ylide with alpha-ylidene-beta-diketones, highly efficient and selective synthesis of optically active dihydrofurans has been achieved.
Abstract: On the basis of the reactions of camphor-derived sulfur ylide with alpha-ylidene-beta-diketones, highly efficient and selective synthesis of optically active dihydrofurans has been achieved.
86 citations
TL;DR: An efficient method for the synthesis of substituted 1(2H)-isoquinolone derivatives via nickel-catalyzed annulation of substituted 2-halobenzamides with alkynes is described and is successfully applied to the total synthesis of oxyavicine with excellent yield.
86 citations
TL;DR: An efficient and convenient method for the synthesis of highly substituted polycyclic pyridinium salts from the reaction of various 2-aryl-pyridines and 2- Daryl-sp(2) -nitrogen-atom-containing heterocycles with alkynes through rhodium(III)-catalyzed CH activation and annulation under an O2 atmosphere is described.
Abstract: An efficient and convenient method for the synthesis of highly substituted polycyclic pyridinium salts from the reaction of various 2-aryl-pyridines and 2-aryl-sp2-nitrogen-atom-containing heterocycles with alkynes through rhodium(III)-catalyzed CH activation and annulation under an O2 atmosphere is described A possible mechanism that involves the chelation-assisted CH activation of the 2-aryl-pyridine substrate, insertion of the alkyne, and reductive elimination is proposed This mechanism was supported by the isolation of a five-membered rhodacycle (I′) In addition, kinetic isotope studies were performed to understand the intimate reaction mechanism
86 citations
TL;DR: NHC-catalyzed divergent annulation of enals with heterocyclic enones was developed to produce benzofuran/indole-containing ε-lactones or spiro-heterocycles in a highly diastereo- and enantioselective fashion.
86 citations
TL;DR: Highly potent bryostatin analogues which contain the complete bRYostatin core structure have been synthesized using a pyran annulation approach as a key strategic element.
Abstract: Highly potent bryostatin analogues which contain the complete bryostatin core structure have been synthesized using a pyran annulation approach as a key strategic element. The A ring pyran was assembled using a pyran annulation reaction between a C1−C8 hydroxy allylsilane and an aldehyde comprising C9−C13. This pyran was transformed to a new hydroxy allylsilane and then coupled with a preformed C ring aldehyde subunit in a second pyran annulation, with concomitant formation of the B ring. This tricyclic intermediate was elaborated to bryostatin analogues which displayed nanomolar to subnanomolar affinity for PKC, but displayed properties indistinguishable from a phorbol ester in a proliferation/attachment assay.
86 citations