Accessing novel fluorinated heterocycles with the hypervalent fluoroiodane reagent by solution and mechanochemical synthesis
作者:William Riley、Andrew C. Jones、Kuldip Singh、Duncan L. Browne、Alison M. Stuart
DOI:10.1039/d1cc02587b
日期:——
A new and efficient strategy for the rapid formation of novel fluorinated tetrahydropyridazines and dihydrooxazines has been developed by fluorocyclisation of β,γ-unsaturatedhydrazones and oximes with the fluoroiodane reagent. Mechanochemical synthesis delivered fluorinated tetrahydropyridazines in similar excellent yields to conventional solution synthesis, whereas fluorinated dihydrooxazines were
BF<sub>3</sub>·OEt<sub>2</sub>-mediated cyclization of β,γ-unsaturated oximes and hydrazones with <i>N</i>-(arylthio/arylseleno)succinimides: an efficient approach to synthesize isoxazoles or dihydropyrazoles
作者:Wei Yu、Shichao Yang、Pei-Long Wang、Pinhua Li、Hongji Li
DOI:10.1039/d0ob01388a
日期:——
A highly efficient BF3·OEt2-mediated cyclization of β,γ-unsaturatedoximes and tosylhydrazones with N-(arylthio/arylseleno)succinimides has been established for the construction of N-heterocycles in a one-step manner. This metal-free cyclization provides direct access to isoxazoles and dihydropyrazoles in good to excellent yields at room temperature. The mechanistic experiments support the formation
Catalytic Enantioselective Iodoetherification of Oximes
作者:Chandra Bhushan Tripathi、Santanu Mukherjee
DOI:10.1002/anie.201304173
日期:2013.8.5
The first catalyticenantioselectiveiodoetherification of oximes is developed using commercially available N‐iodosuccinimide. In the presence of a dihydrocinchonidine‐derived thiourea (10 mol %), β,γ‐unsaturated oximes undergo facile iodoetherification to produce Δ2‐isoxazolines containing a quaternary stereogenic center generally in high yield with good to excellent enantioselectivity.
Room temperature iron(<scp>ii</scp>)-catalyzed radical cyclization of unsaturated oximes with hypervalent iodine reagents
作者:Shichao Yang、Hongji Li、Pinhua Li、Jingya Yang、Lei Wang
DOI:10.1039/c9ob02424g
日期:——
Here, we disclose an iron(ii)-catalyzed I-O bond cleavage of Koser's hypervalent iodine reagents (HIRs) that initiated the radical cyclization of unsaturated oximes at room temperature. This strategy is successfully applied for the construction of the isoxazoline backbone in an efficient manner. In particular, the direct introduction of a TsO group into products facilitates their late-stage transformations