cheminform abstract: enantioselective generation of benzylic stereocenters mediated by a remote...

2000 stereochemistry stereochemistry (general, optical resolution) O 0030 45 - 036 Enantioselective Generation of Benzylic Stereocenters Mediated by a Remote Sulfoxide. — The reaction of optically active o-sulﬁnyltoluene derivatives (I) with LDA generates benzyllithium carbanions, which on reaction with various electrophiles aﬀord the corresponding adducts with highly diastereoselective 1,4-induction. Thus, the stereogenic benzylic center is generated with absolute diastereoselectivity, and only for the additional stereocenter, which is generated with asymmetrically substituted carbonyl compounds, epimeric mix- tures are obtained [cf. (VII)/(VIII) and (X)/(XI)]. Removal of the auxiliary is smoothly achieved on reaction with Raney nickel (no reaction conditions given). — (GARCIA RUANO, JOSE L.; CARRENO, M. CARMEN; TOLEDO, MIGUEL A.; AGUIRRE, JOSE M.; ARANDA, M. TERESA; FISCHER, JEAN; Angew. Chem., Int. Ed. 39 (2000) 15, 2736-2737; Dep. Quim. Org., Fac. Cienc., Univ. Auton., Cantoblanco, E-28049 Madrid, Spain; EN) 1

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Page 1: ChemInform Abstract: Enantioselective Generation of Benzylic Stereocenters Mediated by a Remote Sulfoxide

2000 stereochemistry

stereochemistry (general, optical resolution)O 0030

45 - 036Enantioselective Generation of Benzylic Stereocenters Mediated bya Remote Sulfoxide. — The reaction of optically active o-sulfinyltoluenederivatives (I) with LDA generates benzyllithium carbanions, which on reactionwith various electrophiles afford the corresponding adducts with highly diastere-oselective 1,4-induction. Thus, the stereogenic benzylic center is generated withabsolute diastereoselectivity, and only for the additional stereocenter, which isgenerated with asymmetrically substituted carbonyl compounds, epimeric mix-tures are obtained [cf. (VII)/(VIII) and (X)/(XI)]. Removal of the auxiliary issmoothly achieved on reaction with Raney nickel (no reaction conditions given).— (GARCIA RUANO, JOSE L.; CARRENO, M. CARMEN; TOLEDO,MIGUEL A.; AGUIRRE, JOSE M.; ARANDA, M. TERESA; FISCHER,JEAN; Angew. Chem., Int. Ed. 39 (2000) 15, 2736-2737; Dep. Quim. Org.,Fac. Cienc., Univ. Auton., Cantoblanco, E-28049 Madrid, Spain; EN)

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