Synthesis and Properties of ortho-t-BuSO2C6H4-Substituted Iodonium Ylides

Abstract

Iodonium ylides have recently attracted much attention on account of their synthetic applications. However, only a limited number of reports concerning the properties and reactivity of iodonium ylides exist, which is partly due to their instability. In this study, we synthesized several iodonium ylides that bear both an electron-withdrawing group and an aromatic ring with an ortho-t-BuSO2 group. Based on the crystal structures of the synthesized iodonium ylides in combination with natural-bond-orbital (NBO) calculations, we estimated the strength of the intra- and intermolecular halogen-bonding interactions. In addition, we investigated the reactivity of the iodonium ylides under photoirradiation.

Exploring the role of halogen bonding in iodonium ylides: insights into unexpected reactivity and reaction control

“…The reaction pathways followed by iodonium ylides and Lewis basic reaction partners, from the initial adducts they form to the different products they produce, has long been a cause for discussion. This concept was elegantly illustrated by Kobayashi and Takemoto ( Scheme 1 ) [ 101 ], who suggested that an ylide 1 may halogen bond with a nucleophile using either of its σ-holes to generate intermediates 2 or 3 , where the cis -oriented ligands may reductively eliminate to generate either a functionalized β-dicarbonyl ( 4 , most common) or a substituted arene ( 5 , rare). Interestingly, when the first iodonium ylide was synthesized by Neiland and co-workers in 1957, they also evaluated its decomposition [ 1 , 102 ].…”

Editorial: Advanced Research in Halogen Bonding

“…Y. Takemoto, Y. Kobayashi and co-authors report the successful synthesis of orthot BuSO 2 C 6 H 4 -substituted iodonium ylides (which are known for their variety of synthetic applications) [7]. This research group estimate the strength of the intra-and intermolecular halogen-bonding interactions in the ylides salts and investigate their photoreactions.…”

N-Acylimino-λ3-iodanes from the Metathesis of Iodosoarenes and Nitriles for the Photoinduced C–H Perfluoroacylamination of (Hetero)Arenes

“…14 We chose ortho-SO 2 -t-Bu-substituted iodobenzene diacetate 13a,b (1) for its expected reactivity as well as the potential solubility and stability of the corresponding products. 16 The treatment of trifluoroacetamide (3a) and 1 with sodium hydride in dichloromethane at −20 °C successfully afforded N-trifluoroacetylated iminoiodane 5a in a 72% yield (entry 1). However, the use of pentafluoro-npropanaminde (3b) and heptafluoro-n-butanamide (3c) resulted in decreased yields (entries 2 and 3, respectively), presumably due to the poorer nucleophilicities of the perfluorinated amides.…”

“…We began by preparing a series of N -perfluoroacylated iminoiodanes according to a reported procedure that used an iodoarene diacetate and a perfluorinated amide under basic conditions (conditions A, Table ). We chose ortho -SO 2 - t -Bu-substituted iodobenzene diacetate , ( 1 ) for its expected reactivity as well as the potential solubility and stability of the corresponding products . The treatment of trifluoroacetamide ( 3a ) and 1 with sodium hydride in dichloromethane at −20 °C successfully afforded N -trifluoroacetylated iminoiodane 5a in a 72% yield (entry 1).…”

“…This difference could be due to an additional XB interaction between the lone pair of the carbonyl oxygen and the σ* orbital of the C–I bond in the planar conformer. To estimate the scale of the intramolecular XB interactions, a natural bond orbital (NBO) analysis was performed using the Gaussian Program (Figure B). , In all cases, strong interaction energies (ca. 5–6 kcal/mol) were observed between the iodine atom and the ortho -SO 2 - t -Bu groups.…”