Highly Efficient One-Pot Synthesis of 2,4,5-Trisubstituted 3(2H)-Furanones Utilizing a Au(I)-Catalyzed Oxidation/Pinacol Rearrangement/anti-Michael Cascade

Abstract

A highly efficient Au(I)-catalyzed cascade reaction between bispropargylic alcohols and pyridine-N-oxides has been realized. The reaction process involved a gold(I)-catalyzed sequential oxidation/ Pinacol rearrangement/oxacyclization. Moreover, 1,2-aryl, 1,2-alkyl, or 1,2-vinyl migration was favored over 1,2-alkynyl in the crucial gold(I)catalyzed Pinacol rearrangement step. A range of 2,4,5-trisubstituted 3(2H)-furanones were synthesized in high yields (up to 88%) with excellent regioselectivities (up to >19:1) under mild reaction conditions.3(2H)-Furanone structural units are commonly observed in several naturally occurring products, such as bullatenone, merrekentrone C, inotilone, tuscoron C, jatrophone, and cephalimysin A, which exhibit a wide range of biological activities in medicinal chemistry (Figure 1). 1−3 As a result, these heterocycles have received considerable attention in recent years, and a number of synthetic strategies have been developed to build the crucial 3(2H)-furanone frameworks. 3−10 Among them, one of the most representative and efficient approaches is acid-or base-catalyzed oxacyclization of acetylenic β-diketones (Scheme 1a). 4−6 However, it is worth