The operationally simple crosscoupling procedure is general, regiospecific with regard to the propargyl nucleophile, and shows complete selectivity for products of orthopropargylation over. In addition, the connective pummerer type cyclisation has been. In summary, pyrrole and pyrazole sulfoxides undergo orthoallylation by a heterocycleaccelerated interrupted pummererthioclaisen rearrangement sequence. The pummerer rearrangement, whereby sulfoxides react with electrophiles to give. For the love of physics walter lewin may 16, 2011 duration. The sulfinatesulfone pummerer rearrangement article pdf available in phosphorus sulfur and silicon and the related elements 951. Request permission export citation add to favorites track citation. Aug 02, 20 in summary, pyrrole and pyrazole sulfoxides undergo orthoallylation by a heterocycleaccelerated interrupted pummererthioclaisen rearrangement sequence. The pummerer rearrangement, exemplified by the reaction of a sulfoxide, 1. The 3,3sigmatropic rearrangement delivery mechanism ensures that cc bond formation.
Regioselective synthesis of c3 alkylated and arylated. Jun 05, 2019 the libretexts libraries are powered by mindtouch and are supported by the department of education open textbook pilot project, the uc davis office of the provost, the uc davis library, the california state university affordable learning solutions program, and merlot. Metalfree approach to biaryls from phenols and aryl sulfoxides by. Pummerer reaction of sulfoxides in acetic anhydride catalyzed by almcm41. The website doesnt require users to pay for its services. Development of a pummerer type cyclisation for an approach. Phosphorus, sulfur silicon relat, elem 1991 120 and 121,145. The acetate then acts as a catalyst to induce an elimination reaction to produce the cationic thial structure 4, with acetic acid as byproduct.
From the 18 otracer studies, the asymmetric induction at. The libretexts libraries are powered by mindtouch and are supported by the department of education open textbook pilot project, the uc davis office of the provost, the uc davis library, the california state university affordable learning solutions program, and merlot. Pummerer rearrangement results in oxidation of the carbon atom adjacent to the sulfoxide group at the same time the sulfoxide is reduced to sulfide. The reaction appears to be optimal using dimethyl sulfoxide as the substrate. Thus, ozonization of the tetrahydrothiophene 224 in ch 2 cl 2 at. The pummerer rearrangement was first reported by rudolf pummererin 1903. Examples of both inter and intramolecular reactions are now widespread. Procter a a dual vicinal functionalisation cascade involving the. Depending upon the nature of the substituent at the. The first step involving acetylation of the sulfoxide with release of acetate is found to be ratedetermining in both cases. All structured data from the file and property namespaces is available under the creative commons cc0 license. The pummerer rearrangement is an organic reaction whereby an alkyl sulfoxide rearranges to. Files are available under licenses specified on their description page. The synthesis of the requisite sulfoxide 3 was envisaged to arise from the xanthenepcarboxylic ester 4, which in turn was prepared by ullmann condensation of 6.
Masakatsu shibasaki and coworkers at the university of tokyo have recently published in aciee on the total synthesis of enthyperforin, a polyprenylated acylphloroglucinol. The sila pummerer reaction, which is also discussed in this chapter, is the rearrangement of sulfoxides bearing a silyl group on the. Recent advances in pummerer reactions springerlink. The treatment of sulfoxides with acid anhydrides or acid chlorides brings about a reaction called the pummerer rearrangement, which gives. Arylsulfinyl groups direct the metalfree, regiospecific, nucleophilic orthoallylation of pyrroles and pyrazoles. The mechanism of the pummerer rearrangement begins with the acylation of. Facile synthesis of oligofluoroalkyl sulfides, abstract upon treatment with nbu4nh2f3 and 1,3dibromo5,5dimethylhydantoin, various organic sulfides were readily fluorinated to. The interrupted pummerer reaction and, surprisingly, the resulting 3,3sigmatropic rearrangement occurred at or below ambient temperature cf. Sulfoxidedirected metalfree orthopropargylation of. A pummerer rearrangement route to sugar vinyl sulfides and synthesis of 3deoxy3alkylarylsulfinyl pyranosides 2,3unsaturated enoses. Therefore, sulfoxides and sulfides can be considered as aldehyde precursors. The pummerer reaction of sulfinyl compounds lucchi. The strategy has been adapted to allow regiospecific propargylation of the heterocyclic substrates.
In addition, the connective pummerertype cyclisation has been. Dft calculations are used to investigate the mechanism of the pummerer reaction between a chiral sulfoxide and acetic anhydride under classical and stereoselective reaction conditions without and with additives, respectively. The mechanism of pummerer rearrangement has been investigated using. We report a pummerer rearrangement of methionine sulfoxide treated. Key to the catalytic process is the capture and inversion of reactivity of a 2.
Isatoic anhydrides, pummerer rearrangement, smethyl 2. Rearrange pages in pdf online pdf candy edit pdf free. Many scholars of chemistry do not hesi te to point out that the names associated with name reactions are often not the actual inventors. The operationally simple and metalfree process allows the addition of allylic and propargylic nucleophiles with ch substitution and shows complete regiospecificity with regard to both. Request pdf on the thermal pummerer rearrangement of substituted sulfoxides sulfoxides bearing thioester and ester groups at the. A connective pummerertype cyclisation has been developed for an approach to the synthesis of ecteinascidin 597. Facile synthesis of oligofluoroalkyl sulfides, abstract upon treatment with nbu4nh2f3 and 1,3dibromo5,5dimethylhydantoin, various organic sulfides were readily fluorinated to give. From a mechanistic point of view there are many other reactions, sometimes given specific names, such as the sommelethauser, stevens, and vilsmeier rearrangements, that appear to resemble the. The pummerer and pummerertype reactions of sulfoxides generate sulfonium ion intermediates, to which either internal or external nucleophilic species add to form carboncarbon and carbonheteroatom bonds at the. We also acknowledge previous national science foundation support under grant numbers 1246120, 1525057. The rearranged products can be hydrolyzed to give aldehydes.
Pdf candy provides a great easy in use and free way of rearranging pages in a pdf file online. In this reaction, sulfur is reduced while adjacent carbon is oxidized. Dual vicinal functionalisation of heterocycles via an interrupted pummerer coupling3,3sigmatropic rearrangement cascade mindaugas. The first total syntheses of triptobenzene t, vitexifolin c, 4epitriptobenzene l, triptobenzene l, and nepetaefolin f have been accomplished through an enantioselective, common intermediate approach and have enabled the confirmation andor establishment of the absolute stereochemistry of each natural product synthesized. While the reaction can be conducted in the absence of a base, yields of isolated product are higher in the presence of a base. We also acknowledge previous national science foundation support under grant numbers 1246120, 1525057, and 14739. Mar 20, 2017 the interrupted pummerer reaction and, surprisingly, the resulting 3,3sigmatropic rearrangement occurred at or below ambient temperature cf. For instance, the arndteistert reaction has nothing to do with either arndt or eistert, pummerer did not discover the pummerer rearran ment, and even the famous birch reduction owes its initial. Nucleophilic orthoallylation of pyrroles and pyrazoles. Several electron rich glyoxamide substrates have been prepared and conditions for the connective pummerertype cyclisation have been developed successfully. Dual vicinal functionalisation of heterocycles via an. An example of this isomerization is the acidic hydrolysis of an borneoltype substance to give camphenelike structures, the wm rearrangement camphene rearrangement type i and the nametkin isomerization camphene rearrangement type ii products respectively. Only one isomer at the stereogenic sulfur center of. Procter a a dual vicinal functionalisation cascade involving the union of heterocycles and allyl sulfoxides is described.
Mar 22, 20 dft calculations are used to investigate the mechanism of the pummerer reaction between a chiral sulfoxide and acetic anhydride under classical and stereoselective reaction conditions without and with additives, respectively. Pdf candy offers a free and fast way to rearrange pages in pdf. Mechanisms and synthetic applications of the pummerer reaction. Designed for practitioners of organic synthesis, this book helps chemists understand and take advantage of rearrangement reactions to enhance the synthesis of useful chemical compounds.
Sulfoxidedirected metalfree crosscouplings in the expedient synthesis of. Nov, 2018 for the love of physics walter lewin may 16, 2011 duration. Nov 21, 2010 this page was last edited on 22 april 2019, at 18. Pummerer sulfoxide rearrangement an overview sciencedirect. On the thermal pummerer rearrangement of substituted sulfoxides. Mechanistic studies support the intermediacy of allylsulfonium salts that undergo facile thioclaisen rearrangement onto the heterocyclic ring, giving products of coupling. Other articles where pummerer rearrangement is discussed. The synthesis of the requisite sulfoxide 3 was envisaged to arise from the xanthenepcarboxylic ester 4, which in turn was prepared by ullmann condensation of 6 with 7 followed by cyclization of the resulting diphenyl ether 5. Determination of methionine sulfoxides in peptides. Molecular rearrangements in organic synthesis ebook, 2015.
The mechanism of pummerer rearrangement has been investigated using carbohydratebased thioethers as substrates, and ozone as the oxidant employed to convert the sulfides to sulfoxides 2006ja227. Wikimedia commons has media related to rearrangement reactions this category is part of a classification scheme based on the royal society of chemistry reaction names ontology, compiled by colin bachelor, celia gitterman and david barden. An efficient, metalfree approach to c3 and c2 arylated an. Reaction of pummerer rearrangement intermediate with thiols. Application of three new andor underutilized pummerer reaction. The pummerer rearrangement has been widely studied and has received considerable attention as a synthetically useful process. Several electron rich glyoxamide substrates have been prepared and conditions for the connective pummerer type cyclisation have been developed successfully. Posts about pummerer rearrangement written by naturalproductman. A sulfoxidedirected, metalfree orthopropargylation of aromatics and heteroaromatics exploits intermolecular delivery of a propargyl nucleophile to sulfur followed by an intramolecular relay to carbon. The mechanism of the pummerer rearrangement begins with the acylation of the sulfoxide resonance structures 1 and 2 by acetic anhydride to give 3, with acetate as byproduct. The pummerer rearrangement is an organic reaction whereby an alkyl sulfoxide rearranges to an.
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