583872-73-5Relevant articles and documents
Palladium-catalyzed cascade reaction of α,β-unsaturated sulfones with aryl iodides
Mauleon, Pablo,Nunez, Angel A.,Alonso, Ines,Carretero, Juan C.
, p. 1511 - 1520 (2003)
Unlike traditionally used acyclic 1,2-disubstituted alkenes, the reaction of α,β-unsaturated phenyl sulfones with aryl iodides under Heck reaction conditions (Pd(OAc)2 as catalyst, Ag2-CO3 as base in DMF at 120°C) takes place mainly by a cascade process, involving one unit of the alkene and three units of the aryl iodide, to afford a substituted 9-phenylsulfonyl-9,10-dihydrophenanthrene, The dominant formation of this 3:1 coupling product, instead of the Heck trisubstituted olefin, shows that aromatic C-H activation processes can compete with the usually fast syn β-hydrogen elimination step in the Heck arylation of an acyclic olefin. The structural scope of this palladium-catalyzed cascade arylation of α,β-unsaturated sulfones has proved to be wide with regard to substitution at the β-position (alkyl, aryl, or alkenyl substitution), substitution at the sulfone unit (alkyl or phenyl sulfones), and configuration at the C=C bond (trans or cis). Moreover, although less favored than in the case of the arylation of α,β-unsaturated sulfones, similarly substituted 9,10-dihydrophenanthrenes have also been obtained in the case of α,β-unsaturated phosphine oxides and α,β-unsaturated phosphonate esters. A Pd0-pdII-pdIV mechanistic pathway involving the successive formation of highly electrophilic σ-alkylpalladium intermediates and palladacycles is proposed for this multi-component arylation.
Catalytic enantioselective 1,3-dipolar cycloaddition of azomethine ylides with vinyl sulfones
Llamas, Tomas,Arrayas, Ramon Gomez,Carretero, Juan C.
, p. 1795 - 1798 (2007/10/03)
A general protocol for the enantioselective catalytic 1,3-dipolar cycloaddition of azomethine ylides with aryl vinyl sulfones is described. Nearly complete exo selectivity and enantioselectivities up to 85% ee are attained with Cu(CH3CN)4