Chiral carbonyl hypoiodites

Abstract

Three chiral carbonyl hypoiodites, R-C(O)OI, have been prepared from N-protected (S)-valine to give the ligand-stabilised (S)-valinoyl hypoiodite complexes with 4-dimethylaminopyridine, 4-pyrrolidinopyridine, and 4-morpholinopyridine as the stabilising ligands. The identity of...

Halogen Bonds of Halogen(I) Ions─Where Are We and Where to Go?

“…15 Importantly, the N−Br and N−I bond lengths of substituted analogues vary insignificantly and are independent of the bond strength. 82 This observation is also in line with the strength independence of the N−I bond lengths of [bis(pyridine)iodine(I)] + complexes, 62 56 The influence of substituents on the stability and the geometry of halogen(I) complexes has been extensively studied using solution NMR, X-ray diffraction, and computations. 45,62,63,80 In short, electron-donating substituents strengthen while electron-withdrawing ones weaken the 3c4e halogen bond.…”

“…15,52 This protocol is typically performed in CH 2 Cl 2 but also works using other aprotic solvents, such as CH 3 CN. 53 Being a robust procedure, it can be applied for the preparation of halogen(I) complexes using various Lewis bases to yield virtually any type of [D 55,56 analogues. Importantly, this procedure is unlikely to provide pure product in the presence of protic solvents, such as alcohols or water, which have been used in some initial protocols.…”

“…62,63 The (relative) stabilities of complexes formed upon the interaction of a halogenated Lewis base with a Journal of the American Chemical Society 6c. This reaction is most relevant for the estimation of the energies of the asymmetric halogen-bond complexes of, for instance, Nhalosaccharins, 50 N-halosuccinimides, 112 and hypoiodates 55,56 as well as of fluorine-centered halogen-bond complexes. 19 The energy cost of stretching a D−X covalent to a D ■ APPLICATIONS Halogen Transfer Reactions.…”

Iodine(I) and Silver(I) Complexes Incorporating 3-Substituted Pyridines

“…The stability of halogen­(I) complexes follows the trend: I > Br ≫ Cl, , which is reflected in the number of solid-state examples reported for each type, with Barluenga’s reagent, bis (pyridine)­iodine­(I) tetrafluoroborate, being the paradigm of iodine­(I) complexes due to its widespread use in a multitude of organic transformations as a mild iodinating and oxidizing reagent. − Halogen­(I) complexes, [L–X–L] + , feature a 3-center 4-electron ( 3c–4e ) bond, the symmetric nature of which has been confirmed computationally and in solution. , The negatively charged [O–I–O] − complexes are also known to have applications as organic reagents, and recently the ability to instigate asymmetry in the halogen bonding, via hydrogen bonding with one of the two saccharinato ligands, in the analogous [N–I–N] − complexes has been demonstrated . Interest in halogen­(I) chemistry has been steadily increasing in recent years, with a whole slew of recent advances being reported, including the first examples of unrestrained heteroleptic, − hierarchical, and nucleophilic interactions of iodine­(I) complexes, − as well as the resurgence of (isolable) non-chiral ,− and chiral carbonyl hypoiodites in the context of being halogen-bonded iodine­(I) complexes.…”

N−X⋅⋅⋅O−N Halogen Bonds in Complexes of N‐Haloimides and Pyridine‐N‐oxides: A Large Data Set Study

“…Over the last decade, the + IÀ N XBs in [NÀ IÀ N] + has received much attention [36] and they are now being utilized for constructing capsules, [37,38] helicates [39] and metal-organic frameworks (MOFs) [40] unrestrained homoleptic [41,42] and heteroleptic [43][44][45] and hierarchical, [46] and nucleophilic interactions of iodine(I) complexes, [47][48][49] as well as stable nonchiral [50][51][52] and chiral carbonyl hypoiodites. [53] Compared to the much more explored CÀ I•••N XB systems, [44] oxygen atom as an XB acceptor has not attracted so much intention due to its lower nucleophilicity and inherent polydentate nature and electron ''push-pull'' property (Figure 2). However, the significance of X•••O(carbonyl/ether) interactions has been demonstrated in protein-drug complexes [54,55] and crystal engineering.…”