α-Ketophosphonates as Ester Surrogates: Isothiourea-Catalyzed Asymmetric Diester and Lactone Synthesis
摘要:
Isothiourea HBTM-2.1 catalyzes the asymmetric Michael addition/lactonization of aryl- and alkenylacetic acids using alpha-keto-beta,gamma-unsaturated phosphonates as alpha,beta-unsaturated ester surrogates, giving access to a diverse range of stereodefined lactones or enantioenriched functionalized diesters upon ring-opening.
Asymmetric construction of phosphono dihydropyranones from α-ketophosphonates enabled by Pd/chiral isothiourea relay catalysis
作者:Mostafa Sayed、Zhipeng Shi、Zhi-Yong Han、Liu-Zhu Gong
DOI:10.1039/d3ob01267k
日期:——
the synthesis of chiral phosphono dihydropyranones. This approach is enabled by Pd/chiral isothiourea relay catalysis under mild reaction conditions, starting from readily available benzyl bromides, CO, and α-ketophosphonates. The cascade reactioninvolves the generation of a ketene intermediate from Pd-catalyzed carbonylation of benzyl bromide and subsequent chiral Lewis base catalyzed formal [4 +