homoallyl sulfones were prepared from homoallyl alcohols, which are easily accessible through the recently reported Lewis acid isomerization of oxetanes. The iridium-catalyzed asymmetric hydrogenation of homoallylic sulfones afforded γ-chiral sulfones with excellent enantioselectivities (up to 98% ee). The synthetic potential of this novel methodology was demonstrated by the total synthesis of (R)-(−)-curcumene
报道了一种制备手性甲基苄基化合物的新方法。末端高烯丙基砜是由高烯丙醇制备的,可以通过最近报道的氧杂环丁烷的路易斯酸异构化轻松获得。铱催化的高烯丙基砜的不对称氢化提供了具有优异对映选择性(高达 98% ee)的 γ-手性砜。 ( R )-(−)-姜黄烯的全合成证明了这种新颖方法的合成潜力。
Exploiting the Lithiation-Directing Ability of Oxetane for the Regioselective Preparation of Functionalized 2-Aryloxetane Scaffolds under Mild Conditions
作者:Donato Ivan Coppi、Antonio Salomone、Filippo Maria Perna、Vito Capriati
DOI:10.1002/anie.201109113
日期:2012.7.23
Oxetane nudges in the DoM direction! Regioselective ortho‐lithiation induced by an oxetane ring has been achieved. The reaction provides easy access to ortho‐functionalized 2‐aryloxetanes also through a lithiation/borylation Suzuki–Miyaura cross‐coupling. The lithiation‐directing ability of oxetane and the proton transfer mechanism have been investigated by competitive metalation and kinetic isotope