aryl iodine catalysts by utilization of (i) industrial waste (chloramphenicol base) as the scaffold and (ii) inexpensive amino acid residue (threonine) as the chiral source. Our chiral aryl iodine(III) catalysts bearing H-bond donors and a tunable chiral pocket have been successfully applied in diverse, robust asymmetric oxidative transformations, e.g., dearomatization, spirolactonization, direct C(sp2)–H/C(sp3)–H
尽管通过高价碘进行的不对称催化氧化反应的研究领域取得了显着进展,其程序简单、效率高、立体选择性高,并且在绿色有机催化范式下开发其高度可扩展、环境友好和可持续的方案以进一步工业转化仍然存在过去几十年来,合成有机化学和工艺工程领域面临着长期的挑战。在此,我们利用(i)工业废物(氯霉素碱)作为支架和(ii)廉价的氨基酸残基(苏氨酸)作为手性源,设计并合成了一个构象灵活且可回收的芳基碘催化剂的新库。我们的带有氢键供体和可调手性口袋的手性芳基碘( III )催化剂已成功应用于多种稳健的不对称氧化转化,例如脱芳构化、螺内酯化、直接C(sp 2 )–H/C(sp 3 ) –H交叉偶联和氟化。我们的工艺采用无塔分离方法、易于操作和升级合成,催化剂易于回收,特别是通过沉淀回收。
Phenyliodine Bis(trifluoroacetate)-Mediated Oxidative C–C Bond Formation: Synthesis of 3-Hydroxy-2-oxindoles and Spirooxindoles from Anilides
The reaction of phenyliodine bis(trifluoroacetate) (PIFA) with a series of anilides 1 (E = CO2Et) In CF3CH2OH was found to give 3-hydroxy-2-oxindole derivatives 2, while that with various anilides 1' (E = CON(R-4)Ar) afforded the C-2-symmetric or unsymmetric spirooxindoles 3. These processes feature a metal-free oxidative C(sp(2))-C(sp(3)) bond formation, followed by oxidative hydroxylation or spirocyclization.
Asymmetric Organocatalytic Direct C(sp<sup>2</sup>)H/C(sp<sup>3</sup>)H Oxidative Cross-Coupling by Chiral Iodine Reagents
作者:Hua Wu、Yu-Ping He、Lue Xu、Dong-Yang Zhang、Liu-Zhu Gong
DOI:10.1002/anie.201309967
日期:2014.3.24
An asymmetric organocatalytic direct CH/CHoxidativecoupling reaction of N1,N3‐diphenylmalonamides has been well established by using chiral organoiodine compounds as catalysts, wherein four CH bonds were stereoselectively functionalized to give structurally diverse spirooxindoles with high levels of enantioselectivity. More importantly, the findings indicated that chiral hypervalent organoiodine
不对称的有机催化直接Ç H / C ħ氧化偶联反应Ñ 1,Ñ 3 -diphenylmalonamides已经很好地利用建立手性有机碘化合物作为催化剂,其特征在于,四号丙 H键被立体选择性地官能化以得到具有高结构多样spirooxindoles对映选择性水平。更重要的是,这些发现表明,手性高价有机碘试剂可作为替代催化剂,用于创建无活性CH键的对映选择性官能化。