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
作者:Guoqiang Zhou、Daniel Lim、Don M. Coltart
DOI:10.1021/ol801498u
日期:2008.9.1
Thioesters undergo chemoselective soft enolization and acylation by N-acylbenzotriazoles on treatment with MgBr(2)center dot OEt(2) and i-Pr(2)NEt to give beta-keto thioesters. Prior enolate formation is not required, and the reaction is conducted using untreated CH(2)Cl(2) 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.
A Practical Synthesis of β-Keto Thioesters by Direct Crossed-Claisen Coupling of Thioesters and N-Acylbenzotriazoles
作者:Don Coltart、Guoqiang Zhou、Daniel Lim、Fang Fang
DOI:10.1055/s-0029-1216971
日期:2009.10
Thioesters undergo chemoselective soft enolization and acylation with N-acylbenzotriazoles on treatment with MgBr2ËOEt2 and i-Pr2NEt to give β-keto thioesters. Prior enolate formation is not required and the reaction is conducted using untreated dichloromethane open to the air.