Key Laboratory of Molecular Target & Clinical Pharmacology, School of Pharmaceutical Sciences & the Fifth Affiliated Hospital , Guangzhou Medical University , Guangzhou , Guangdong 511436 , China.
Dalian Institute of Chemical Physics , Chinese Academy of Sciences , Dalian 116023 , China.
Org Lett. 2018 Jul 6;20(13):3892-3896. doi: 10.1021/acs.orglett.8b01477. Epub 2018 Jun 13.
An efficient and redox-neutral synthesis of 2 H-chromene-3-carboxylic acids from N-phenoxyacetamides and methyleneoxetanones has been realized via a solvent-controlled and rhodium(III)-catalyzed C-H activation/unusual [3 + 3] annulation sequence. This transformation represents the first example of using an α-methylene-β-lactone unit as the three-carbon source in transition-metal-catalyzed C-H activations through selective alkyl C-O bond cleavage. Synthetic applications and mechanistic details, including further derivatization of 2 H-chromene-3-carboxylic acids, the isolation and identification of a five-membered rhodacycle, as well as the theoretical studies for reasoning a plausible Rh(III)-Rh(V)-Rh(III) process, have also been discussed.
通过溶剂控制和铑(III)催化的 C-H 活化/不寻常的[3 + 3]环加成序列，实现了从 N-苯氧基乙酰胺和亚甲基氧杂环丁酮高效、氧化还原中性合成 2H-色烯-3-羧酸。这种转化代表了使用α-亚甲基-β-内酰胺单元作为过渡金属催化 C-H 活化中通过选择性烷基 C-O 键断裂的三碳源的第一个例子。还讨论了合成应用和反应机理细节，包括 2H-色烯-3-羧酸的进一步衍生化、五元铼环的分离和鉴定，以及理论研究，以推理合理的 Rh(III)-Rh(V)-Rh(III)过程。
