Highly stereoselective and efficient synthesis of ω-heterofunctional di- and trienoic esters for Horner–Wadsworth–Emmons reaction via alkyne hydrozirconation and Pd-catalyzed alkenylation
作者:Guangwei Wang、Zhihong Huang、Ei-ichi Negishi
DOI:10.1016/j.tetlet.2009.02.023
日期:2009.7
(E)-BrCHCHCO2Et and (E)-BrCHC(Me)CO2Et using PEPPSI-IPr (7) as a catalyst provides a highly efficient and selective (⩾98% all-E) route to ω-hydroxy di- and trienoic acid esters (1a–6a). The corresponding phosphonate esters (1c–4c) of ⩾98% isomeric purity can be obtained via conventional bromination–phosphonation in >80% yields. As expected, their carbonyl olefination is ca. 85–90% E-selective with alkyl aldehydes