21403-38-3Relevant articles and documents
Light-Enabled Radical 1,4-Aryl Migration Via a Phospho-Smiles Rearrangement
De Abreu, Maxime,Belmont, Philippe,Brachet, Etienne
, p. 3758 - 3767 (2021/02/01)
Rearrangement reactions in organic chemistry are attractive strategies to build efficiently complex scaffolds, in just one step, from simple starting materials. Among them, aryl migrations are certainly one of the most useful and straightforward rearrangement for building attractive carbon-carbon bonds. Of note, anionic aryl migration reactions have been largely described compared to their radical counterparts. Recently, visible-light catalysis has proven its efficiency to generate such radical rearrangements due to the concomitant loss of a particle (often CO2 or SO2), which is the driving-force of the reaction. Here, we disclose a Smiles-type rearrangement, triggered by a phosphorus-containing unit (arylphosphoramidate), therefore called "phospho-Smiles"rearrangement, allowing a Csp2-Csp2 bond formation thanks to a 1,4-aryl migration reaction. In addition, combining this approach with a radical hydroamination/amination reaction produces an amination/phospho-Smiles cascade particularly attractive, for instance, to investigate the synthesis of the phthalazine core, a scarcely described scaffold of interest for medicinal chemistry projects.
Vinylogous Nicholas reactions in the synthesis of bi- and tricyclic cycloheptynedicobalt complexes
Kolodziej, Izabela,Green, James R.
, p. 10852 - 10864 (2015/11/17)
The Lewis acid mediated intramolecular Nicholas reactions of allylic acetate enyne-Co2(CO)6 complexes afford cycloheptenyne-Co2(CO)6 complexes in three manifestations. Electron rich aryl substituted alkyne complexes give tricyclic 6,7,x-benzocycloheptenyne complexes, with x = 5, 6, or 7. Allylsilane substituted complexes afford exo methylene bicyclic x,7-cycloheptenyne complexes (x = 6,7). The allyl acetate function may also be replaced by a benzylic acetate, to afford dibenzocycloheptyne-Co2(CO)6 complexes. Following reductive complexation, the methodology may be applied to the synthesis of the icetexane diterpene carbon framework.
Formation of condensed 1 H-pyrrol-2-ylphosphonates and 1,2-dihydropyridin- 2-ylphosphonates via Kabachnik-fields reaction of acetylenic aldehydes and subsequent 5-exo-dig or 6-endo-dig cyclizations
Buk?naitienè, Rita,Urbanaitè, Aurelija,?ikotienè, Inga
, p. 6532 - 6553 (2014/08/05)
Kabachnik-Fields reactions of various carbocyclic or heterocyclic acetylenic aldehydes together with subsequent Lewis acid catalyzed cyclizations have been studied. It was found that 5-exo-dig versus 6-endo-dig cyclization mode strongly depends on the structure of starting materials. Thus, nonaromatic acetylenic α-anilinomethylphosphonates underwent gold(III)-catalyzed or iodine-mediated 5-exo-dig cyclization to 1H-pyrrol-2-ylphosphonates. In contrast, electron-withdrawing heteroaromatic substrates formed 1,2-dihydropyridin-2-ylphosphonate ring containing materials via an exclusive 6-endo-dig ring-closure process. The dual mode of cyclization is possible only for α-amino (2-alkynylphenyl)methylphosphonates containing a benzene ring.
