| Over the past few decades,hypervalent iodine reagents have proved to be very valuable and versatile in organic synthesis.In addition to being used as oxidants,they can also initiateα-functionalization of carbonyl compounds,ligand exchange reactions,oxidative coupling processes and other chemical transformations.Hypervalent iodine reagents are favored by the synthetic community for their wide range of reactivity,mild reaction conditions,and often as green,environmentally friendly alternatives in chemical reactions associated with toxic heavy metals.In organic chemistry,halides have always occupied a very important position,from the synthesis of natural products,drugs and pesticides to materials science and molecular recognition,organic halides have been used as a large number of synthetic precursors and target compounds.Therefore,halogenation is one of the most widely used reactions in the field of chemistry.Although there are many halogenation methods for the diversity of different substrates at present,the wide application of hypervalent iodine compounds provides many new possibilities for the development of halogenation.At present,a variety of hypervalent iodine reagents have appeared in the halogenation of compounds,some as direct halogenation reagents to provide halogen atoms,others as catalysts,instead of many toxic heavy metal catalysts,providing a new and diverse catalytic path for different substrates.It has become another hot field in the development of halogenation.Oxazoline is one of the most common heterocyclic compounds found in many natural products and drug molecules.It has been found as antifungals,antibacterials and antituberculosis agents.Oxazoline is one of the most important types of five-memeral heterocyclic compounds and is also a typical intermediate in organic synthesis route.Currently,many methods have been reported for the synthesis of functionalized oxazoline derivatives from carboxylic acids,aldehydes,nitriles,esters,alkenes,carbonyl compounds andβ-hydroxy amides.In our work,various halogenated 2-oxazoline derivatives were synthesized by allyl amides catalyzed by high price iodine reagent and use BF3·Et2O,TMSCI and TMSBr as halogen source compounds.The method is expected to be an effective strategy for the synthesis of2-oxazoline in future applications,with mild reaction conditions,wide range of substrates,strong functional group tolerance and high yield. |
