Transition metal catalysis and nucleophilic fluorination
Transition metal catalysis and nucleophilic fluorination
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DOI：
10.1039/c2cc16158c
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发表时间：
2012-01-01
影响因子：
4.9
通讯作者：
Gouverneur, Veronique
中科院分区：
文献类型：
--
作者：
Hollingworth, Charlotte;Gouverneur, Veronique
利用氟化试剂进行过渡金属催化转化制备有合成价值的氟化靶标得到了广泛的发展。这是一个对促进含氟药品和农用化学品的实验室和工业化学合成至关重要的课题。由于基于正电子发射断层扫描（PET）的功能成像越来越多地用于诊断和药物开发，放射化学也正在成为一个充满活力的研究领域。本文综述了氟源如何用于催化亲核氟化的各种底物，包括三氟化芳基、炔、烯丙基卤化物、烯丙基酯、烯丙基三氯乙酸酯、苯基卤化物、叔烷基卤化物和环氧化物。直到最近，这一研究领域的进展一直缓慢，部分原因是与氟（亲核试剂或碱）的双重反应性有关的挑战。尽管困难重重，一些显著的突破还是出现了。这包括证明Pd(0)/Pd（II）催化的亲核氟化反应从三氟化芳基酯中获得氟芳烃是可行的，以及使用烯丙基氯化物或带有o -离去基的烯丙基前体与氟化物进行Tsuji-Trost烯丙基烷基化的第一个例子。最近，烯丙基氟化物也在铱催化下可得。另一种反应是介观环氧化物的催化不对称氢氟化反应，在仔细的机理研究的基础上得到了极大的改进。值得注意的是，迄今为止报告的每一种过渡金属催化的亲核氟化都使用不同的f试剂，这一观察结果表明，这一研究领域将受益于更大的亲核氟源池。在这方面，最近一项引人注目的进展是成功地设计、合成和应用了氟化物衍生的亲电晚期氟化试剂。这种新型试剂可以极大地促进临床前和临床PET成像。
Transition metal catalyzed transformations using fluorinating reagents have been developed extensively for the preparation of synthetically valuable fluorinated targets. This is a topic of critical importance to facilitate laboratory and industrial chemical synthesis of fluorine containing pharmaceuticals and agrochemicals. Translation to F-18-radiochemistry is also emerging as a vibrant research field because functional imaging based on Positron Emission Tomography (PET) is increasingly used for both diagnosis and pharmaceutical development. This review summarizes how fluoride sources have been used for the catalytic nucleophilic fluorination of various substrates inclusive of aryl triflates, alkynes, allylic halides, allylic esters, allylic trichloroacetimidates, benzylic halides, tertiary alkyl halides and epoxides. Until recently, progress in this field of research has been slow in part because of the challenges associated with the dual reactivity profile of fluoride (nucleophile or base). Despite these difficulties, some remarkable breakthroughs have emerged. This includes the demonstration that Pd(0)/Pd(II)-catalyzed nucleophilic fluorination to access fluoroarenes from aryl triflates is feasible, and the first examples of Tsuji-Trost allylic alkylation with fluoride using either allyl chlorides or allyl precursors bearing O-leaving groups. More recently, allylic fluorides were also made accessible under iridium catalysis. Another reaction, which has been greatly improved based on careful mechanistic work, is the catalytic asymmetric hydrofluorination of meso epoxides. Notably, each individual transition metal catalyzed nucleophilic fluorination reported to date employs a different F-reagent, an observation indicating that this area of research will benefit from a larger pool of nucleophilic fluoride sources. In this context, a striking recent development is the successful design, synthesis and applications of a fluoride-derived electrophilic late stage fluorination reagent. This new class of reagents could greatly benefit preclinical and clinical PET imaging.