22791-80-6Relevant articles and documents
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Galli,C. et al.
, p. 1258 - 1261 (1979)
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A Total Synthesis of (±)-Ceratopicanol via Palladium Catalyzed Reductive Cyclization
Kim, Rira,Lee, Hee-Yoon,Lee, Jaeyeon,Lee, Sanghyeon
, (2020)
An efficient total synthesis of ceratopicanol was achieved through successive Pd catalyzed reductive cycloaddition and cyclization reactions. The Pd mediated cyclization reaction to form a triquinane structure demonstrated that a small structural difference changed the reaction pathway either to form different structures or reduced non-cyclized product depending on the reaction conditions.
Primary Anion–π Catalysis of Epoxide-Opening Ether Cyclization into Rings of Different Sizes: Access to New Reactivity
Matile, Stefan,Paraja, Miguel
supporting information, p. 6273 - 6277 (2020/02/28)
The concept of anion–π catalysis focuses on the stabilization of anionic transition states on aromatic π surfaces. Recently, we demonstrated the occurrence of epoxide-opening ether cyclizations on aromatic π surfaces. Although the reaction proceeded through unconventional mechanisms, the obtained products are the same as those from conventional Br?nsted acid catalysis, and in agreement with the Baldwin selectivity rules. Different mechanisms, however, should ultimately lead to new products, a promise anion–π catalysis has been reluctant to live up to. Herein, we report non-trivial reactions that work with anion–π catalysis, but not with Br?nsted acids, under comparable conditions. Namely, we show that the anion–π templated autocatalysis and epoxide opening with alcoholate–π interactions can provide access to unconventional ring chemistry. For smaller rings, anion–π catalysis affords anti-Baldwin oxolanes, 2-oxabicyclo[3.3.0]octanes, and the expansion of Baldwin oxetanes by methyl migration. For larger rings, anion–π templated autocatalysis is thought to alleviate the entropic penalty of folding to enable disfavored anti-Baldwin cyclizations into oxepanes and oxocanes.
Catalytic Asymmetric Synthesis of Cyclohexanes by Hydrogen Borrowing Annulations
Armstrong, Roly J.,Akhtar, Wasim M.,Young, Tom A.,Duarte, Fernanda,Donohoe, Timothy J.
supporting information, p. 12558 - 12562 (2019/08/16)
Hydrogen borrowing catalysis serves as a powerful alternative to enolate alkylation, enabling the direct coupling of ketones with unactivated alcohols. However, to date, methods that enable control over the absolute stereochemical outcome of such a process have remained elusive. Here we report a catalytic asymmetric method for the synthesis of enantioenriched cyclohexanes from 1,5-diols via hydrogen borrowing catalysis. This reaction is mediated by the addition of a chiral iridium(I) complex, which is able to impart high levels of enantioselectivity upon the process. A series of enantioenriched cyclohexanes have been prepared and the mode of enantioinduction has been probed by a combination of experimental and DFT studies.
