Triflic anhydride is a versatile electrophile that is able to activate poor nucleophiles. Herein, we show that readily available β-keto esters are activated by Tf2O furnishing γ-pyrones. Mechanistic studies suggest that this transformation proceeds via a double triflation, formation of an oxocarbenium intermediate and dealkylation promoted by a crucial nitrile additive.
三氟甲磺酸酐是一种通用的亲电试剂,能够活化较差的亲核试剂。在本文中,我们表明,容易获得的β-
酮酸酯通过提供
γ-吡喃酮的Tf 2 O活化。机理研究表明,这种转变是通过双重
三氟甲磺酸酯化,氧羰基中间体的形成以及关键的腈类添加剂促进的脱烷基而进行的。