24509-88-4Relevant articles and documents
Catalytic asymmetric synthesis of chiral allylic esters
Cannon, Jeffrey S.,Kirsch, Stefan F.,Overman, Larry E.
supporting information; experimental part, p. 15185 - 15191 (2010/12/25)
A broadly useful catalytic enantioselective synthesis of branched allylic esters from prochiral (Z)-2-alkene-1-ols has been developed. The starting allylic alcohol is converted to its trichloroacetimidate intermediate by reaction with trichloroacetonitrile, either in situ or in a separate step, and this intermediate undergoes clean enantioselective SN2′ substitution with a variety of carboxylic acids in the presence of the palladium(II) catalyst (Rp,S)-di-μ-acetatobis[(η5- 2-(2′-(4′-methylethyl)oxazolinyl)cyclopentadienyl-1-C,3′-N) (η4-tetraphenylcyclobutadiene)cobalt]dipalladium, (R p,S)-[COP-OAc]2, or its enantiomer. The scope and limitations of this useful catalytic asymmetric allylic esterification are defined.
ALKYLATION DES IONS CARBOXYLATES PAR LES SELS DE SULFONIUM: INFLUENCE DES SELS DE CUIVRE
Badet, B.,Julia, M.,Ramirez-Munoz, M.,Sarrazin, C. A.
, p. 3111 - 3126 (2007/10/02)
Sulfonium salts are extremely powerful alkylating agents, particularly in the two-phase technique both solid-liquid and liquid-liquid.Alkylation of carboxylate salts by sulfonium salts does not show very large dependence on ratio of reactivities of various groups attached to the sulfur and mixtures of esters are often obtained.In the presence of copper(I) salts, there is a strong acceleration of the reaction of allylic sulfonium salts and it becomes very selective in favour of the unsaturated residues.Prenyl sulfonium salts, which react very eficiently through the α-position in the absence of copper salts, give exclusively tertiary esters when a catalytic amount of copper bromide is present.
