The conversion of β-amido esters to β-enamino esters is an indispensable step for some synthetic approaches to alkaloids and related medicines. Known methods for such transformation are not only stepwise, but also proceed with low atom-efficiency. Herein, we report a direct and versatile approach that features the Ir-catalyzed chemoselective reduction of β-amido esters with 1,1,3,3-tetramethyldisiloxane
对于某些生物碱和相关药物的合成方法,β-酰胺基酯向β-烯氨基酯的转化是必不可少的步骤。用于这种转化的已知方法不仅是逐步的,而且以低原子效率进行。本文中,我们报道了一种直接且通用的方法,其特征在于用1,1,3,3-四甲基二硅氧烷(TMDS)进行Ir催化的β-酰胺基酯的化学选择性还原。另外,在某些脂环族β-烯胺酯的13 C NMR光谱中观察到缺少某些信号。这揭示了文献中长期存在但被忽略的现象。
Metal-Free Synthesis of 2-Oxindoles via PhI(OAc)<sub>2</sub>-Mediated Oxidative C–C Bond Formation
The series of 3-monofunctionalized 2-oxindoles 2 were conveniently synthesized from reactions between anilide 1 and phenyliodine(III) diacetate (PIDA) through hypervalent iodine mediated C(sp(2))-C(sp(2)) bond formation followed by a subsequent deacylation reaction. This metal-free method, shown to provide direct access to an important oxindole intermediate, could be applied to the total synthesis of naturally occurring horsfiline.