Design, Preparation, X-ray Crystal Structure, and Reactivity of o-Alkoxyphenyliodonium Bis(methoxycarbonyl)methanide, a Highly Soluble Carbene Precursor

Abstract

The preparation, X-ray structure, and reactivity of new, highly soluble, and reactive iodonium ylides derived from malonate methyl ester and bearing an ortho substituent on the phenyl ring are reported. These new reagents show higher reactivity than common phenyliodonium ylides in the Rh-catalyzed cyclopropanation, C-H insertion, and transylidation reactions under homogeneous conditions.

Preparation, structure, and oxidative reactivity of (dichloroiodo)pyridines: recyclable hypervalent iodine reagents

“…Compound 9 has a pseudocyclic structure with an intramolecular interaction of 3.084(8) Å between the iodine center and the alkoxy group oxygen atom (Figure 1). 24,[26][27][28][29] Similar to 7, the ICl 2 fragment is rotated out of the pyridine plane (85.46 (9)). Two intermolecular I-Cl contacts at about 3.5 Å are present in the X-ray structure of 9 forming a trigonal-bipyramidal motif.…”

Blue LED Irradiation of Iodonium Ylides Gives Diradical Intermediates for Efficient Metal‐free Cyclopropanation with Alkenes

“…Thes cope of this cyclopropanation reaction was then evaluated with the aim of demonstrating the viability of our iodonium ylides with various alkenes (Scheme 3). Thedimethyl malonate-derived ylide 1n was coupled with styrene in 17 ho rw ith Nphenylmaleimide in 7hto furnish 3u and 3v in 64 and 46 % yields.W eo bserved this ylide 1m to undergo significant decomposition upon standing at room temperature,w hich could be overcome by using 20 equiv of styrene,h ence affording 3u in 81 %yield over 3h.Inthe aim of consuming the ylide at af aster rate,w er epeated the experiment using violet LED (l max 397 nm) irradiation, but 3u was observed in only 25 %yield after 1h,along with 27 %ofthe corresponding free carbene dimer.W ealso attempted this reaction using the o-iodoanisole-derived iodonium ylide of methyl acetoacetate (1o), [26] which is fully soluble in the reaction mixture, but no improvement was achieved compared with running the reaction as as lurry (64 %y ield, 22 h). The Meldrumsa cid-derived ylide 1j was coupled with other additional styrene derivatives bearing either electron-donating or electron-withdrawing groups.T he expected cyclopropane products 3d-i were obtained in yields ranging from 72 to 96 %, with the fastest reaction rates occurring with the most electron-rich alkenes.T wo other styrenes featuring abiphenyl motif were also viable,leading to 3j and 3k in 68 %and 75 % yields after 24 hofirradiation.…”

Applications of iodonium salts and iodonium ylides as precursors for nucleophilic fluorination in Positron Emission Tomography

“…Ylides 54 are relatively stable compounds, have good solubility in dichloromethane, chloroform, or acetone (e.g., the solubility of ylide 54, R = Pr, in dichloromethane is 0.56 g/mL), and have higher reactivity than common phenyliodonium ylides in the Rh-catalyzed cyclopropanation, C-H insertion, and transylidation reactions under homogeneous conditions. 90 Cardinale and Ermert have developed a simplified procedure for the synthesis of aryliodonium ylides directly from the respective aryliodides. 84 In particular, aryliodonium-(5-[2,2-dimethyl-1,3-dioxane-4,6-dione]) ylides 58 were synthesized by the two-step one-pot procedure shown in Scheme 27.…”