Torres-Ochoa Rubén O, Leclair Alexandre, Wang Qian, Zhu Jieping
Laboratory of Synthesis and Natural Products, Institute of Chemical Sciences and Engineering, École Polytechnique Fédérale de Lausanne, EPFL-SB-ISIC-LSPN, BCH 5304, 1015, Lausanne, Switzerland.
Chemistry. 2019 Jul 17;25(40):9477-9484. doi: 10.1002/chem.201901079. Epub 2019 May 10.
In the presence of a catalytic amount of iron(III) acetylacetonate [Fe(acac) ], the reaction of structurally diverse ketoxime esters with trimethylsilyl azide (TMSN ) afforded γ-azido ketones in good to excellent yields. This unprecedented distal γ-C(sp )-H bond azidation reaction went through a sequence of reductive generation of an iminyl radical, 1,5-hydrogen atom transfer (1,5-HAT) and iron-mediated redox azido transfer to the translocated carbon radical. TMSN served not only as a nitrogen source to functionalise the unactivated C(sp )-H bond, but also as a reductant to generate the catalytically active Fe species in situ. Based on the same principle, a novel β-C(sp )-H functionalisation of alcohols via N-acyloxy imidates was subsequently realised, leading, after hydrolysis of the resulting ester, to β-azido alcohols, which are important building blocks in organic and medicinal chemistry.
在催化量的乙酰丙酮铁（III）[Fe（acac）₃]存在下，结构多样的酮肟酯与叠氮基三甲基硅烷（TMSN₃）反应，以良好至优异的产率得到γ-叠氮基酮。这种前所未有的远端γ-C（sp³）-H键叠氮化反应经历了亚胺基自由基的还原生成、1,5-氢原子转移（1,5-HAT）以及铁介导的氧化还原叠氮基转移至迁移的碳自由基的一系列过程。TMSN₃不仅作为使未活化的C（sp³）-H键官能化的氮源，还作为原位生成催化活性铁物种的还原剂。基于相同原理，随后实现了通过N-酰氧基亚胺酯对醇进行新型β-C（sp³）-H官能化，在所得酯水解后得到β-叠氮基醇，它们是有机化学和药物化学中的重要结构单元。
