32539-83-6Relevant articles and documents
Borowitz et al.
, p. 1234 (1973)
Radical α–alkylation of ketones with unactivated alkenes under catalytic and sustainable industrial conditions
Sanz-Navarro, Sergio,Garnes-Portolés, Francisco,López-Cruz, Carlos,Espinós-Ferri, Estela,Corma, Avelino,Leyva-Pérez, Antonio
, (2021/02/12)
The industrially–viable aerobic α–alkylation of cyclic and acyclic ketones with allyl and alkyl alkenes in the presence of catalytic amounts of Mn2+, under homo– and heterogeneous conditions, is achieved here. The substitution of organic peroxides by Mn2+ either as a simple soluble salt or supported in zeolites, in air, generates in–situ peracid radicals and circumvents the aggressiveness of current industrial protocols, to pave the way for the design of sustainable aerobic catalytic systems. Combined reactivity and mechanistic studies show that large cyclic ketones stabilize a radical in the α–position due to a higher polarizability, steric hindrance and no proximity effects. As a proof of concept, the gram–scale synthesis of the industrial fragrance exaltolide is carried out with the Mn2+ catalysts in air, which clearly improves any other previously reported method not only in safety and environmental terms but also in number of synthetic steps and overall yield.
Ring-expansion reaction of 1-hydroperoxy-16-oxabicyclo[10.4.0]hexadecane catalyzed by copper ions: Use in the synthesis of 15-pentadecanolide
Ogibin,Terent'ev,Nikishin
, p. 1166 - 1169 (2007/10/03)
A catalytic procedure has been developed for the synthesis of 15-pentadecanolide (1) from readily available 1-hydroperoxy-16-oxabicyclo[10.4.0]hexadecane (2). The method is based on the reaction of hydroperoxide 2 with copper acetate (0.15-5 mol.%). Ring expansion occurred as a result of generation of tertiary bicyclohexadecyloxyl radicals 4 from hydroperoxide 2 under the action of CuI ions, β-scission of the radicals accompanied by regioselective cleavage of the bridge bond to form macrocyclic C-centered radicals 5, and their oxidation by CuII ions to (E)-11- and (E)-12-pentadecen-15-olides (6). The products obtained were converted into 15-pentadecanolide by subsequent catalytic hydrogenation over a Pd catalyst in a yield of more than 90% with respect to hydroperoxide 2.
