15295-69-9Relevant articles and documents
A Sequential Homologation of Alkynes and Aldehydes for Chain Elongation with Optional 13C-Labeling
Brunner, Andreas,Hintermann, Lukas
, p. 2787 - 2792 (2016/02/27)
Terminal alkynes (RCCH) are homologated by a sequence of ruthenium-catalyzed anti-Markovnikov hydration of alkyne to aldehyde (RCH2CHO), followed by Bestmann-Ohira alkynylation of aldehyde to chain-elongated alkyne (RCH2CCH). Inverting the sequence by starting from aldehyde brings about the reciprocal homologation of aldehydes instead. The use of 13C-labeled Bestmann-Ohira reagent (dimethyl ((1-13C)-1-diazo-2-oxopropyl)phosphonate) for alkynylation provides straightforward access to singly or, through additional homologation, multiply 13C-labeled alkynes. The labeled alkynes serve as synthetic platform for accessing a multitude of specifically 13C-labeled products. Terminal alkynes with one or two 13C-labels in the alkyne unit have been submitted to alkyne-azide click reactions; the copper-catalyzed version (CuAAC) was found to display a regioselectivity of >50 000:1 for the 1,4- over the 1,5-triazine isomer, as shown analytically by 13C NMR spectroscopy.
Nitrone dipolar cycloaddition routes to piperidines and indolizidines. Part 9. Formal synthesis of (-)-pinidine and total synthesis of (-)-histrionicotoxin, (+)-histrionicotoxin and (-)-histrionicotoxin 235A
Davison, Edwin C.,Fox, Martin E.,Holmes, Andrew B.,Roughley, Stephen D.,Smith, Catherine J.,Williams, Geoffrey M.,Davies, John E.,Raithby, Paul R.,Adams, Joseph P.,Forbes, Ian T.,Press, Neil J.,Thompson, Mervyn J.
, p. 1494 - 1514 (2007/10/03)
An intramolecular hydroxylamine-alkyne cyclisation is used for the enantioselective synthesis of the cyclic nitrones 36 and 44. We have demonstrated the use of a novel nitrone protection strategy by cycloaddition of styrene to the cyclic nitrone 44 in the synthesis of the spirocyclic core of the histrionicotoxin family of alkaloids. Deprotection by dipolar cycloreversion of the styrene adduct (the bicyclic isoxazolidine 39) and in situ intramolecular dipolar cycloaddition of a pendant (Z)-α,β-unsaturated nitrile to the intermediate nitrone 50 gave the isoxazolidine 51 in high yield with a surprising degree of regioselectivity compared with the corresponding (Z)-enyne 36. The method is amenable to the synthesis of both enantiomers 51 and 62 of the tricyclic core structure which can be converted by way of the common intermediates (e.g. 53 and ent-53) respectively into the natural configuration of alkaloids (-)-histrionicotoxin 1 and (-)-histrionicotoxin 235A 65 as well as the unnatural (+)-histrionicotoxin 63.
Pesticidal compounds
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, (2008/06/13)
The present invention provides a class of novel substituted bicyclooctanes which have pesticidal activity, particularly against arthropod pests. Pesticidal formulations containing the compounds of the formula (I), their use in the control of pests and methods for their preparation are also disclosed.
