二氟烯醇硅醚作为含氟砌块在构建有机氟化物中的研究进展

Difluorinated Silyl Enol Ethers as Fluorine-Containing Building Blocks for the Synthesis of Organofluorine Compounds

与非氟化合物相比,有机氟化合物由于其特殊的化学和物理性质被广泛应用于药物开发、临床医学、农业化学、材料科学和有机合成等领域.在过去的几十年中,在选择性氟化和氟烷基化合成结构多样的含氟分子方面取得了重大进展.其中,α-氟烷基化羰基代表了生物活性和药物分子中一类重要的分支骨架.在此背景下,基于使用二氟烯醇硅醚(DFSEE)作为独特的氟代烷基化试剂,已经实现了多种引入偕二氟烷基化羰基片段的有效方法,包括羟醛反应、曼尼希反应、芳基化反应、烯丙基化反应、质子化反应、卤化反应、共轭加成反应和烯化反应等.另一方面,DFSEE凭借其优异的反应灵活性,还能与自由基型二氟烷基化和级联反应等新型反应模式相融合.此外,还报道了DFSEE参与的O位选择性加成反应,能够构建多功能的偕二氟烯烃.鉴于有机氟化合物的重要性和基于二氟烯醇硅醚作为反应物参与合成含氟化合物途径的巨大潜力,重点介绍了DFSEE作为关键含氟功能化砌块合成氟化物的最新研究进展.

Organofluorine compounds have been widely applied in various fields ranging from drug discovery,clinical medicines,agrochemistry,and materials science to organic synthesis,due to their special chemical and physical properties when compared with nonfluorinated analogs.In the past decades,significant progress has been made in the development of selective fluorination and fluoroalkylation for the synthesis of structurally diverse fluorine-containing molecules.Among them,theα-fluoroalkylated carbonyl group represents an important class of scaffold components in biologically active and druglike compounds.In this context,based on the use of difluorinated silyl enol ether(DFSEE)as a unique fluoroaklylating reagent,a variety of methods for the incorporation of gem-difluoroalkylated carbonyl moiety have been achieved,including aldol,Mannich,arylation,allylation,protonation,halogenation,conjugate addition,and olefination reactions.On the other hand,DFSEEs could also merge with new types of reactions such as radical-type difluoroalkylation and cascade reaction by virtue of their incredible reactive flexibility.In addition,the O-site selective addition of DFSEEs was also reported,enabling the construction of versatile gem-difluoroalkenes.Given the importance of organofluorine compounds and the synthetic potential of these avenues,herein,we highlight the recent advances in the functionalization of gem-difluorinated silyl enol ethers,which serve as key fluorine-containing building blocks for the synthesis of organofluorine compounds.