Bin Sun,Xiaohui Zhuang,Jieli Yin,Kesheng Zhang,Haiyun Zhao,Can Jin
The photoredox-catalyzed radical difluoroalkylation/cyclization/hydroxylation cascade reaction of various 2-bromo-2,2-difluoro-N-arylacetamides containing unactivated alkene moieties has been developed, providing green and efficient access to various 4-hydroxyalkyl-3,3-difluoro-γ-lactams. Control experiments confirmed a radical process, and inexpensive air acted as the sole hydroxy resource. In addition, the highlights of this protocol include good tolerance for a variety functional groups, lower photocatalyst loading, and ease of operation.
Hanyang Zhang,Wen Liu,Jiale Hu,Qian Zhang,Zeguo Fang,Dong Li
An efficient method involving copper-catalyzed trifluoromethylthiolation and radical cyclization ofN-phenylpent-4-enamides using readily available and stable AgSCF3as the trifluoromethylthiolating reagent is described. The method enables the synthesis of a series of potential medicinally valuable trifluoromethylthio-substitutedγ-lactams and relative 2-oxazolidinone derivatives with broad functional group compatibility. Mechanistic investigations indicated that this reaction involved amidyl radical-initiated cascade5-exo-trigcyclization followed by trifluoromethylthiolation, resulting in the formation of new C-N and C-S bonds.
A novel non-heme chloroperoxidase (SvGL) with promiscuous (−)-γ-lactamase activity towards Vince lactam was identified from Streptomyces viridochromogenes by genome data-mining. SvGL possesses high activity and excellent thermal stability and enantioselectivity. Furthermore, it is able to tolerate extremely high substrate concentrations (4.0 M, 436.5 g L−1). Using the newly discovered (−)-γ-lactamase as a biocatalyst, an efficient and environmentally benign process for the production of (+)-γ-lactam was developed. The process allowed an enantioselective resolution of 436.5 g L−1 racemic γ-lactam with only 0.2 g L−1 lyophilized cell-free extract, affording an extremely high substrate/catalyst ratio of 2183 (g g−1), a space-time yield of 458 g L−1 d−1, and a very low E factor (environmental factor) of 5.7 (kg waste per kg product) even when the process water is included.
危险品化学品经营许可证（带存储）