Cu<sup>0</sup>-Promoted Cyclisation of Unsaturated α-Halogeno Amides To Give β- and γ-Lactams
作者:Andrew J. Clark、Jonathan N. Duckmanton、Fulvia Felluga、Armando Gennaro、Franco Ghelfi、Jack R. D. Hardiman、Abdirisak A. Isse、Claudia Manferdini、Domenico Spinelli
DOI:10.1002/ejoc.201600249
日期:2016.5
Efficient 5-exo-trig atom-transfer radicalcyclisation of 13 unsaturated α-halogeno amides mediated by Cu0 (copper wire) with tripyridylmethanimine ligand (TPMA; 1 mol-%) in a mixed solvent of EtOAc/EtOH (3:1) is reported (89–98 %), with recycling of the copper wire. A substantial improvement in conversion and selectivity was obtained when Na2CO3 (5 mol-%) was added to the reaction mixture. The Cu0
Stereodivergent atom-transfer radical cyclization by engineered cytochromes P450
作者:Qi Zhou、Michael Chin、Yue Fu、Peng Liu、Yang Yang
DOI:10.1126/science.abk1603
日期:2021.12.24
Naturallyoccurring enzymes can be a source of unnatural reactivity that can be molded by directed evolution to generate efficient biocatalysts with valuable activities. Owing to the lack of exploitable stereocontrol elements in synthetic systems, steering the absolute and relative stereochemistry of free-radical processes is notoriously difficult in asymmetric catalysis. Inspired by the innate redox
N-heterocyclic carbene (NHC)-catalyzed tandem cyclization/addition/cyclization reaction of 2-isocyanobiaryls and α-bromo-N-cinnamylamides for the synthesis of 2-pyrrolidinone-functionalized phenanthridines is developed. This protocol features a radical cascade process, broad substrate scope, and good functional group compatibility under metal- and oxidant-free reaction conditions.
A novel Fe-catalyzed fluorosulfonylation of alkenes with Na2S2O4 and N-fluorobenzenesulfonimide (NFSI) for assembling various lactam-functionalized alkyl sulfonyl fluorides is disclosed. In this reaction, Na2S2O4 acts as both an SO2 source and a reductant. Furthermore, the resulting products can be efficiently transformed into valuable chemicals, including sulfonyl esters and sulfonamides, via the
公开了一种新的Fe催化烯烃与Na 2 S 2 O 4和N-氟苯磺酰亚胺(NFSI)的氟磺酰化反应,用于组装各种内酰胺官能化的烷基磺酰氟。在该反应中,Na 2 S 2 O 4既充当SO 2源又充当还原剂。此外,通过六氟化硫交换(SuFEx)点击反应,所得产品可以有效转化为有价值的化学品,包括磺酰酯和磺酰胺。初步机理研究表明该转化通过分子内自由基环化、SO 2插入、亚硫酸根阴离子形成和氟化进行。
Alkyl Radical Initiated Cyclization/Cascade for Synthesizing Lactam‐Substituted Alkyl Sulfones
An alkyl radical initiated cyclization/tandem reaction of alkyl bromides and alkyl electrophiles by using potassium metabisulphite (K2S2O5) as a connector is developed for the synthesis of various lactam-substituted alkyl sulfones. Notably, this process does not require a metal catalyst or metal powder reductant, highlighting its environmentally friendly features. The reaction demonstrates outstanding
开发了使用偏亚硫酸氢钾 (K 2 S 2 O 5 ) 作为连接剂的烷基溴和烷基亲电子试剂的烷基自由基引发的环化/串联反应各种内酰胺取代的烷基砜的合成。值得注意的是,该过程不需要金属催化剂或金属粉末还原剂,凸显了其环保特点。该反应表现出出色的底物适应性和对不同官能团的高度耐受性。此外,经过后期修饰的生物活性分子和市售药物也与这种转变高度兼容。机理研究表明,该反应通过一步过程进行,包括分子内自由基环化、“SO 2 ”插入和外部烷基掺入。