110450-38-9Relevant articles and documents
Silica-Supported Phosphine–Gold Complexes as an Efficient Catalytic System for a Dearomative Spirocyclization
Bibal, Brigitte,Buffière, Sonia,Cao, Zhen,Nlate, Sylvain,Oda, Reiko,Pouget, Emilie,Scalabre, Antoine
, p. 427 - 433 (2021)
The combination of metal catalyst and inorganic silica frameworks provides a greener approach to recyclable catalysis. In this study, three phosphine–gold chloride complexes have been successfully covalently grafted onto chiral silica nanohelices. The resulting 3D ensembles showed chiroptical properties that allowed the monitoring of the supported ligands. The heterogeneous gold chloride catalysts in cooperation with silver triflate exhibited high reactivity in various reactions, especially in the spirocyclization of aryl alkynoate esters, for which a catalytic loading of 0.05 mol % could be employed. The heterogeneous catalysts could be easily recovered and recycled seven or eight times without any loss of efficiency. By adding more silver triflate, 25 cycles with full conversion were achieved owing to a complex catalytic system based on silica and metallic species.
Visible light-mediated: Ipso -annulation of activated alkynes: Access to 3-alkylated spiro[4,5]-trienones, thiaspiro[4,5]-trienones and azaspiro[4,5]-trienones
Manna, Sabyasachi,Someswara Ashwathappa, Puneeth Kumar,Prabhu, Kandikere Ramaiah
supporting information, p. 13165 - 13168 (2020/11/09)
A novel method for chemoselective difunctionalization of activated alkynes for synthesizing 3-alkylated spiro[4,5]-trienones, thiaspiro[4,5]-trienones and spirolactams has been uncovered using photoredox catalysis under visible light conditions. The rarel
New photochemical approaches to the synthesis of chromones
Alvaro, Mercedes,Garcia, Hermenegildo,Iborra, Sara,A. Miranda, Miguel,Primo, Jaime
, p. 143 - 148 (2007/10/02)
Irradiation of the p-methoxyphenyl and p-methylphenyl esters of 2-butynoic, propynoic, 3-(ethylenedioxy)butanoic, 3,3-dimethoxypropanoic and 3-oxobutanoic acids (1-3) affords the corresponding photo-Fries products 4-6. Compound 5a is converted in part into the acetophenone 7a, by way of a Norrish type II photo-reaction, while compound 6a is reluctant to undergo this process, in spite of the fact that it also possess γ-carbonyl hydrogen atoms. From the preparative point of view, the photorearrangement of the esters 1a-d and 2a,c-d is exploitable, while that of 3a proceeds with a lower yield. The differences found in the photochemical behaviour of 2a and 3a show the sharp influence of the acetal group on the course of the reaction. Compounds 4-6 are representative model compounds valuable as direct chromone precursors; in fact, they can be readily cyclized to the chromones 10 under basic or acidic conditions.
