has been accomplished in the presence of a chiral N,N′‐dioxide/[Sc(OTf)3] complex (0.5–2 mol %), delivering the desired vicinal anti‐α‐iodo‐β‐amino carbonyl compounds regioselectively in high yields (up to 97 %) and with excellent diastereoselectivities (>99:1 d.r.) and enantioselectivities (up to 99 % ee). Enantiopure syn‐α‐iodo‐β‐amino products could also be obtained from the isomerization of particular
light‐induced C−H amination of heteroarenes can be accomplished with preformed iodine(III) reagents as the combined oxidant and nitrogen source. The reaction requires the use of a small amount of molecular iodine, which under photochemical activation generates in situ an iodine(I) reagent as the initiator of the radical amination reaction. A total of 32 examples exemplify the broad scope of the transformation
Strong N−X⋅⋅⋅O−N Halogen Bonds: A Comprehensive Study on N‐Halosaccharin Pyridine
<i>N</i>
‐Oxide Complexes
作者:Rakesh Puttreddy、J. Mikko Rautiainen、Toni Mäkelä、Kari Rissanen
DOI:10.1002/anie.201909759
日期:2019.12.16
A study of the strong N-X⋅⋅⋅- O-N+ (X=I, Br) halogen bonding interactions reports 2×27 donor×acceptor complexes of N-halosaccharins and pyridine N-oxides (PyNO). DFTcalculations were used to investigate the X⋅⋅⋅O halogen bond (XB) interaction energies in 54 complexes. A simplified computationally fast electrostatic model was developed for predicting the X⋅⋅⋅O XBs. The XB interaction energies vary
Carbonyl Hypoiodites as Extremely Strong Halogen Bond Donors
作者:Shilin Yu、Jas S. Ward、Khai‐Nghi Truong、Kari Rissanen
DOI:10.1002/anie.202108126
日期:2021.9.13
than any known uncharged halogen bond donor. Modulating the Lewis basicity of the selected pyridinederivatives and carboxylates leads to halogen-bonded complexes where the classical O−I⋅⋅⋅N halogen bond transforms more into a halogen-bonded COO−⋅⋅⋅I−N+ ion-pair (salt) with an asymmetric O−I−N moiety. X-ray analyses, NMR studies, and calculations reveal the halogen bonding geometries of the carbonyl hypoiodite-based
由原位形成的羰基次碘酸盐和芳香族有机碱制备中性卤素键合的 O−I−N 配合物。羰基次碘酸盐具有强极化的碘原子,其 σ 空穴比任何已知的不带电卤素键供体都大。调节所选吡啶衍生物和羧酸盐的路易斯碱度会产生卤素键配合物,其中经典的 O−I⋅⋅⋅N 卤素键更多地转化为卤素键 COO − ⋅⋅⋅I−N +离子对(盐) 具有不对称的 O−I−N 部分。 X 射线分析、NMR 研究和计算揭示了基于羰基次碘酸盐的 O−I−N 配合物的卤素键几何结构,证实了固态下的碘原子更接近吡啶衍生物的 N 原子比其在羧酸根 O 原子处的原始位置。
Cocrystal or Salt: Solid State-Controlled Iodine Shift in Crystalline Halogen-Bonded Systems
NISac···Py-NMe2 complex. An external homogeneous electric field ε applied to this complex (all atoms frozen at the crystalline geometry, except iodine) in either gas phase (ε = 3.7 GV m–1) or periodic pseudo-isolated configuration (ε = 2.8 GV m–1) is able to shift the iodine atom at the crystal geometry, miming the polarization effect induced by the local crystal electric field. The strong influence of