Metal-free intermolecular cyclopropanation between alkenes and iodonium ylides mediated by PhI(OAc)₂·Bu₄NI

Abstract

A rapid, mild and metal-free intermolecular cyclopropanation between iodonium ylides and alkene-containing substrates mediated by PhI(OAc)·BuNI is reported. Iodonium ylides of cyclic and acyclic 1,3-dicarbonyls were reacted with a variety of mono-, di-, tri- and tetra-substituted alkenes of various structural types to give 29 cyclopropanes in up to 97% yield.

Iodide-Mediated Synthesis of Spirooxindolo Dihydrofurans from Iodonium Ylides and 3-Alkylidene-2-oxindoles

“…Previous preparations of this motif employed diazo chemistry, intramolecular cyclizations, [3 + 2] cycloadditions, intramolecular Friedel–Crafts reactions, and annulation strategies . As part of our investigations of iodonium ylides acting as diazo surrogates, we recently discovered that iodonium ylides react with electron-rich styrenes, under the action of PhI­(OAc) 2 and Bu 4 NI, to give dihydrofurans (Figure b) . We envisioned that more rigid, cyclic iodonium ylides (e.g., 2a ) would react with 3-alkylidene-2-oxindoles ( 1 ) to generate 3,3′-spirooxindolo dihydrofurans.…”

“…15 As part of our investigations of iodonium ylides acting as diazo surrogates, 16 we recently discovered that iodonium ylides react with electron-rich styrenes, under the action of PhI(OAc) 2 and Bu 4 NI, to give dihydrofurans (Figure 1b). 17 We envisioned that more rigid, cyclic iodonium ylides (e.g., 2a) would react with 3alkylidene-2-oxindoles (1) to generate 3,3′-spirooxindolo dihydrofurans. This chemistry would offer a mild, metal-free and environmentally benign alternative to existing methodologies, and we report here that under Bu 4 NI catalysis, cyclic iodonium ylides react with alkenes (1) to chemo-, diastereo-, and regioselectively generate spirocyclic dihydrofurans 3 (Figure 1c).…”

“…Reductive elimination of iodobenzene from C generates 3a . We believe the differing reactivity observed for cyclic and acyclic iodonium ylides with 1 (e.g., dihydrofuran vs cyclopropane formation) stems from (a) the fixed proximity of the cyclic enolate oxygen atom with the electrophile (see B ) and (b) the unfavorable steric interactions necessary for cyclopropane formation to occur.…”

Hypervalent iodine-mediated synthesis and late-stage functionalization of heterocycles

“…Murphy's group reported preparation of dihydrofurans 184 by reacting electron-rich styrenes 182 with cyclic iodonium ylides 183 (Scheme 48). 81 The reaction was mediated by PhI(OAc)2 6 in the presence of Bu4NI as an iodine source. Though only few examples were reported, the present method provided bicyclic products 184 in significant yields.…”

Advances in Reactions of Iodonium Ylides

“…2015 年, Afonso 课题组 [26] 报道了一种 β-酮酰胺的 无过渡金属催化的新型 C-H 插入反应. 在碱性条件下 β-酮酰胺与(二乙氧基碘)苯(DIB)反应原位生成碘叶立 德, 随后在温和条件下发生插入反应得到 β-内酰胺产 物 59 (Scheme 图式 13 β-酮酰胺分子内 C-H 插入反应 Scheme 13 Intramolecular C-H insertion reaction of β-ketoamide 2017 年, Takemoto 课题组 [27] 2018 年, 冯小明课题组 [28] 报道了手性 Lewis 酸促使 β-酮酰胺与碘叶立德发生不对称 α-烷基化反应, 在手性 N,N'-二氧化物/Ni(II)配合物 66 存在下, 生成了相应的 1999 年, Ochiai 课题组 [30] 2009 年, Charette 课题组 [7] 在其开发的一种从丙二 图式 18 碘叶立德合成 1,1-环丙烷二酯 Scheme 18 Synthesis of 1,1-cyclopropane diester by iodonium ylide 2017 年, Murphy 等 [31] 报道了在 PhI(OAc…”