通过1,2-迁移过程可实现烯丙醇的电化学氧化双官能化,以合成β-三氟甲基酮。利用CF 3 SO 2 Na作为自由基源可以轻松获得一系列β-三氟甲基酮,而无需使用金属和牺牲性化学氧化剂。重要的是,该协议不仅实现了芳基迁移,而且还提供了烷基迁移产物。另外,电化学催化的环膨胀和克级反应证明了该方案的合成有用性。
Cooperative NHC and Photoredox Catalysis for the Synthesis of β‐Trifluoromethylated Alkyl Aryl Ketones
作者:Qing‐Yuan Meng、Nadine Döben、Armido Studer
DOI:10.1002/anie.202008040
日期:2020.11.2
Despite the great potential of radical chemistry in organic synthesis, N‐heterocyclic carbene (NHC)‐catalyzed reactions involving radical intermediates are not well explored. This communication reports the three‐component coupling of aroyl fluorides, styrenes and the Langlois reagent (CF3SO2Na) to give various β‐trifluoromethylated alkylarylketones with good functional group tolerance in moderate to high
尽管自由基化学在有机合成中具有巨大潜力,但涉及自由基中间体的 N-杂环卡宾 (NHC) 催化反应尚未得到很好的探索。该通讯报道了芳酰氟、苯乙烯和 Langlois 试剂 (CF 3 SO 2 Na)的三组分偶联,通过光氧化还原/NHC 协同催化,以中等到高产率生成各种具有良好官能团耐受性的 β-三氟甲基化烷基芳基酮。烯烃酰基三氟甲基化通过羰基与苄基C-自由基的自由基/自由基交叉偶联进行。羰基自由基是通过原位形成的酰唑鎓离子的 SET 还原产生的,而苄基自由基则源自三氟甲基自由基加成到苯乙烯上。
Organic Photoredox-Catalyzed Synthesis of δ-Fluoromethylated Alcohols and Amines via 1,5-Hydrogen-Transfer Radical Relay
alcohol and amine derivatives catalyzed by 2,4,5,6-tetra(9H-carbazol-9-yl)isophthalonitrile (4CzIPN) was developed. This reaction delivered δ-fluoromethylated free alcohols and amines with in situ deprotection of benzyl protecting group under mild irradiation conditions. 4CzIPN was found to be a competent metal-free photoredox catalyst for activating several types of fluoromethylation reagents including
开发了由2,4,5,6-四(9 H-咔唑-9-基)间苯二甲腈(4CzIPN)催化的苄基保护的均丙醇和胺衍生物的加氢三氟甲基化。该反应递送δ-氟甲基化的游离醇和胺,并在温和的辐射条件下原位去保护苄基保护基。已发现4CzIPN是一种有效的无金属光氧化还原催化剂,可通过氧化猝灭活化CF 3 SO 2 Cl,Togni试剂和2-溴-2,2-二氟乙酸酯,以及通过CF 3 SO 2 Na活化几种类型的氟甲基化试剂。还原淬灭,以使简单的烯烃和迈克尔受体直接进行氢三氟甲基化。
Operationally simple hydrotrifluoromethylation of alkenes with sodium triflinate enabled by Ir photoredox catalysis
作者:Lei Zhu、Lian-Sheng Wang、Bojie Li、Boqiao Fu、Cheng-Pan Zhang、Wei Li
DOI:10.1039/c6cc01944g
日期:——
We reported herein a single component of Ir-photoredox catalyst is capable to catalyze hydrotrifluoromethylation of terminal alkenes and Michael acceptors with sodium triflinate (Langlois reagent) in methanol under an irradiation...
acylfluoroalkylation of a variety of olefins in the presence of various commercially available aromatic aldehydes and fluoroalkyl reagents through N-heterocyclic carbeneorganocatalysis. With this protocol, over 120 examples of functionalized ketones with diverse fluorine substituents have been synthesized in up to 99 % yield with complete regioselectivity. The generality of this catalytic strategy was further