Synthesis of 4-Iodo-3-furanones Utilizing Electrophile-Induced Tandem Cyclization/1,2-Migration Reactions

Abstract

Two protocols for the construction of 4-iodo-3-furanones through a sequence consisting of cyclization and 1,2-migration of 2-alkynyl-2-silyloxy carbonyl compounds were developed. In one, electrophilic cyclization is directly induced by N-iodosuccinimide (NIS). In the second less limited variant, AuCl3 catalyzes the tandem reaction in the presence of NIS to provide highly substituted heterocycles in moderate to excellent yields.

A facile base-promoted domino Michael/O-alkylation reaction for the construction of succinimide-substituted 3(2H)-furanones

“…Under the optimal reaction conditions, the generality of this protocol was studied (Table 3). Firstly, a wide range of maleimides 1a-n was studied (Table 3, entries [1][2][3][4][5][6][7][8][9][10][11][12][13][14]. The maleimides included those bearing electronwithdrawing and electron-donating substituents on the aryl ring, as well as N-alkyl maleimides.…”

“…[1][2][3][4] The significance of these molecules has led to a variety of approaches for the synthesis of substituted 3(2H)-furanones, including acid-catalyzed cyclization-dehydration, 5,6 transformations from furans, 7,8 alkynes [9][10][11][12][13][14][15] and allenes. 16 However, most of these routes require the use of specific substrates and reaction conditions are often harsh.…”

4.07 Electrophilic Cyclization

“…55,56 A useful strategy to construct 2,3-disubstituted furopyridines induced by iodine at room temperature is developed by Arcadi Scheme 23 Two protocols for the synthesis of 4-iodo-3-furanones from 2-alkynyl-2-silyloxy carbonyl compounds have been developed (Scheme 54). 58 A plausible mechanism is described in Scheme 54, which includes a heterocyclization with a 1,2-alkyl shift. As shown in path A, after the formation of iodonium intermediate 231 via the coordination of iodine to the triple bond, oxonium ion 232 could be formed by nucleophilic attack of the carbonyl oxygen.…”

When Alkyne π-Activation Meets Pinacol-Type [1,2]-Rearrangement: On the Invention of Domino Reactions for the Synthesis of Carbocycles and Heterocycles

“…51 Unlike the case of catalytic heterocyclization, the N-iodosuccinimide-mediated reaction provides access to products bearing a substituent at the C4 position, and thereby provides an entry into fully substituted furan-3(2H)-ones through standard cross-coupling reactions. We believe that the formation of 4-iodofuran-3(2H)-ones follows closely the pathway outlined in Scheme 19 for the transition-metal-catalyzed reaction.…”