title: Direct carbon-carbon bond formation via chemoselective soft enolization of thioesters: a remarkably simple and versatile crossed-Claisen reaction applied to the synthesis of LY294002.
abstract: Thioesters undergo chemoselective soft enolization and acylation by N-acylbenzotriazoles on treatment with MgBr2 x OEt2 and i-Pr2NEt to give beta-keto thioesters. Prior enolate formation is not required, and the reaction is conducted using untreated CH2Cl2 open to the air. The coupled products are stable synthetic equivalents of beta-keto acids and can be converted directly into beta-keto esters, beta-keto amides, and beta-diketones under mild conditions. The utility of this carbon-carbon bond-forming method is shown through the synthesis of the PI3-K inhibitor LY294002.
authors.affiliation: Department of Chemistry, Duke University, Durham, North Carolina 27708, USA.
authors.forename: Guoqiang
authors.initials: G
authors.lastname: Zhou
authors.forename: Daniel
authors.initials: D
authors.lastname: Lim
authors.forename: Don M
authors.initials: DM
authors.lastname: Coltart