Iodide-promoted Substitution And Oxidation-annulation Of C=C Bonds Of Olefins

Olefins are a series of common molecules which not only extensively existed in natural and synthetic compounds but also serve as versatile building blocks for generating biological and pharmaceutical products through various chemical conversions.Additionally,the functionalization of olefins is a hot-pot in recent organic-synthesis.Olefins which bearing C=C bond in molecule could undergo substitution reactions(e.g.,halogenation,nitration,cyanation,alkoxylation,amination,C_sp2-C_spx couplings,etc.)and addition reactions(e.g.,hydrogenation-addition,difunctionalization-addition,addition-annulation).Despite great attentions have been drawn and numerous progresses have been achieved on functionalization of olefins,it is still in high demands and is worthwhile for chemists to develop more green and efficient strategies on this direction.In this paper,we would like to make contributions to developing green and mild strategies of substitution and/or addition of olefins using iodides as main catalysts,and simultaneously synthesize some valuable products.The detail works are described as follows:1.A mild oxidation from inorganic ammonium salt into oxynitrides has been disclosed in this work.Under a normal temperature and pressure,ammonium could be rapidly converted into oxynitrides(e.g.,NO,NO₂^-,and NO₃^-)in the promotion of Fe-porphyrins and tert-butyl hydroperoxide(TBHP),which detected by IC,GC-MS/HS,and radical-trapping method.Inspired by this discovery,an ammonium-based nitro-donor nitration of olefin was developed.Employing the obtained ammonium-oxidizing process,olefins could be nitrated and afford desired products nitroolefins using NH₄I as nitro-source.Finally,we proposed a plausible mechanism for nitration reaction based on control experiments and literature data.2.The substitution reaction of olefin with azobis providing cyanation source,which leading to a series of allyl nitriles and butenyl nitriles,has been studied in this paper.Comparing with previous methods,olefin serving as starting material in the synthesis of unsaturated nitriles is considered to be more atom-economic and step-economic.Without requiring metal catalysts,iodine serving as a sole catalyst could achieve this cross-coupling reaction of olefin and azobis.With an optimal condition in hand,most of aromatic olefins and aliphatic olefins could be tolerated and afford desired nitriles in useful yields.When isopropenyl substrates replaced vinyl substrates in the same cyanation,it would afford butenyl nitriles rather than allyl nitriles.To gain insight into the mechanism of cyanation,a series of control experiments have been performed,and then a radical-based mechanism for reaction was proposed.3.The multi-components coupling reaction of olefin,DMSO,and iodine has been conducted in this work.The simple terminal olefins serving as materials could regioselectively synthesize the?-iodoalkenyl sulfides with excellent yields via a terminal disubstitution.After a series of optimization experiments,we obtain an optimal condition for this reaction.We then examined the scope of different terminal olefins under optimal condition,which showed a well toleration for both aromatic and aliphatic substrates.The further application on phenylacetylene has been performed and led to a di-iodoalkenyl sulfides in good yield.Based on some control experimental results,a radical-based reaction pathway was confirmed.4.Tetra-components annulation of two olefins,ammonium salt,and DMSO is investigated.In the promotion of iodide and persulfate,the readily available olefin could couple with ammonium(N-source)and DMSO(O-source)affording 2,4-disubstituted oxazoles.After optimizing for reaction conditions and analyzing structures of products,subsequently,we try to use ketones to replace olefins in a same annulation.Hence,we have further developed another tetra-components annulation of one methylketone,another non-methylketone,(NH₄)₂S₂O₈,and DMSO,which led to2,4-disubstituted and 2,4,5-trisubstituted oxazoles involving aromatic and aliphatic ones.Based on control experiments,we indicate that DMSO was the first time to provide O atom in an annulation reaction.