Ring opening reactions can proceed by either s n 2 or s n 1 mechanisms, depending on the nature of the epoxide and on the reaction conditions. An optimized procedure with the catalyst of choice, mcm41, represents a real alternative to the. The discovery and development of epoxideopening cascades in the jamison group is directly tied to our interest in the ladder polyether family of natural products, which has attracted a great deal of interest in the synthetic organic chemistry community. Importantly, this epoxide ringopening protocol can be used for the introduction of amines in natural products. Research in the jamison group massachusetts institute of. Highly facile biomimetic regioselective ring opening of. Ringopening of epoxides in water accordingly, rao et al.
Epoxides are versatile intermediates that can be ring opened using different nucleophiles to produce a wide variety of valuable chemicals. Ringopening reactions can proceed by either s n 2 or s n 1 mechanisms, depending on the nature of the epoxide and on the reaction conditions. Environmentally benign and highly regioselective ring. Dec 05, 2019 a highly diastereoselective desymmetrization of pquinamines via regioselective ring opening of epoxides and aziridines under mild conditions has been developed. A hafniumbased metalorganic framework as a catalyst for regioselective ring opening of epoxides with a mild hydride source casey j.
Pdf highly regioselective ring opening of epoxides using. Ring opening of epoxides with sodium azide in water. To the best of our knowledge, this type of reaction utilizing nonterminal epoxides as precursors remains elusive. Request pdf incl3catalyzed highly regioselective ring opening of epoxides with thiols epoxides react smoothly with thiols in the presence of 10 mol% incl3 under very mild conditions to afford. The discovery and development of epoxide opening cascades in the jamison group is directly tied to our interest in the ladder polyether family of natural products, which has attracted a great deal of interest in the synthetic organic chemistry community. Therefore a highly regioselective method for the synthesis of bhaloalcohols through direct ring opening of epoxides with elemental iodine and bromine in the presence of h2tpps as new. Depending on the substitution pattern, the reaction proceeds either in a sn1type arylepoxides or a sn2type alkylepoxides fashion. Nickelcatalyzed regiodivergent opening of epoxides with.
A hafniumbased metalorganic framework as a catalyst for regioselective ring opening of epoxides with a mild hydride source. Dedicated to professor siegfried blechert on the occasion of. Without using any catalysts, a variety of epoxides undergo ring opening by aromatic amines to afford the corresponding 1,2amino alcohols in high to excellent yields with good regioselectivity in the presence of water as solvent and under solventfree conditions. We herein report a metal and solventfree acetic acidmediated ringopening reaction of epoxides with amines. The regioselectivity of epoxide ring opening reactions for alcohols is examined using lewis acidic catalysts. Rama rao organic chemistry division 1, indian institute of chemical technology, hyderabad 500 007, india, email. The opening of the epoxide ring with different nitriles ritter reaction takes place with total selectivity and in high yields in the presence of bf 3 et 2 o. Lewis acidic catalytic materials are investigated for the regioselective ring opening of epoxides with alcohols. Abstract the reaction of alcohols with epoxides in the presence. Highly regioselective ringopening of epoxides with amines.
We report that bipyridineligated nickel can mediate the addition of functionalized aryl halides, a vinyl halide, and a vinyl triflate to epoxides under reducing conditions. Zahoor institut fur organische chemie, universitat des saarlandes, d66123 saarbrucken, germany email. A hafniumbased metalorganic framework as a catalyst for regioselective ringopening of epoxides with a mild hydride source casey j. Pdf regioselective ring opening of epoxides with thiols in. This reminded me of the famous experiment involving propene epoxide. Incl3catalyzed highly regioselective ring opening of. The regioselective ring opening of terminal epoxides using phenolic nucleophiles is examined using dimethylaminopyridine dmap as a soluble catalyst and solid catalysts based on silica, polymer, and magnetic nanoparticle solids functionalized with dmap analogues. Indiumi iodidemediated regioselective ring opening of. Regioselective ring opening of epoxides by nucleophiles mediated by lithium bistrifluoromethanesulfonimide. Kiasat, maryam zayadi, mehdi fallah mehrjardi chemistry department, college of science, shahid chamran university, ahvaz 65743169, iran received 2 january 2008. My textbook does not agree with 15 other introductory texts i own, but it does agree with one. The formation of ethyleneimine likely occurs prior to ring opening of epoxide. Representative natural or synthetic products containing aminocyclitol moiety. We found that elemental iodine and bromine are converted to trihalide nucleophiles triiodine and tribromide anion, respectively in the presence of catalytic amounts of mesotetraphenylporphyrins h2tpp.
Regioselectivity of acidcatalyzed ringopening of epoxides. The key step involves a highly regioselective ring opening of epoxides by sodium azide. The carbonylation occurred selectively at the unsubstituted c. High yields of the products and mild reaction conditions using green catalyst and water as a green solvent are some advantages of this procedure.
Amino alcohols by regioselective ring opening of epoxides with aromatic amines catalyzed by tin ii chloride 1, 3. Mar 16, 2006 in conclusion, we have established a regioselective ring opening reaction of epoxides to yield. O bond of the epoxide ring, and this reaction tolerates various functional groups such as alkenyl, halide, hydroxy, and alkyl ether. Synthesis of nsulfonyl aziridines through regioselective. Regioselectivity in the ring opening of epoxides for. Therefore, there is a significant current interest in the ring opening of epoxides. Regioselective ring opening of epoxides with amines using silicabonded ssulfonic acid under solventfree conditions mahmood tajbakhsh, rahman hosseinzadeh, parizad rezaee, and heshmatollah alinezhad faculty of chemistry, mazandaran university, babolsar, iran. Pdf biotf 3 catalyzed regioselective ring opening of. The nonenzymatic ring opening reactions of epoxides provide a nice overview of many of the concepts we have seen already in this chapter. Cd is an efficient catalyst for the aminolysis of aromatic amines with styrene oxide derivatives 4 and highly reactive glycidyl ethers 5 in diluted water 15 ml per 1.
A synthetically useful regioselective epoxide ringopening. Without using any catalysts, a variety of epoxides undergo ringopening by aromatic amines to afford the corresponding 1,2amino alcohols in high to excellent yields with good regioselectivity in the presence of water as solvent and under solventfree conditions. Regioselective ring opening of epoxides using nh scn. Regioselective ring opening of epoxides with amines using. An observation on the regioselectivity of ringopening of.
If the epoxide is asymmetric, the structure of the product will. The ppncoco4 and bf3et2o catalyzed carbonylation of simple and functionalized epoxides in dme gives the corresponding. An efficient catalyst for regioselective ring opening of epoxides with alcohols and water. Interestingly, the two amine groups are differently protected. Regioselective ring opening of epoxides using nh scnsilica. The enantioenriched epoxides were accessed by asymmetric epoxidation of the corresponding alkenes catalyzed by the enzyme chloroperoxidase using hydrogen peroxide. Highly regioselective ring opening of epoxides using nan 3. Biotf 3 catalyzed regioselective ring opening of epoxides with phenols. Regioselective ringopenings of epoxides are useful and versatile methods for the construction of functionalized, enantio andor diasteromerically enriched organic compounds. Since our approach is dependent on the ringopening of. The key step involves a highly regioselective ring opening of. Importantly, this epoxide ringopening protocol can be used for the introduction of amines in natural products during latestage transformations.
In summary, a simple, rapid, economical and an effective route for the alcoholysis of epoxides and therefore the friedelcrafts alkylation of indoles and pyrroles via an basically regioselective ring opening of epoxides with aliphatic and aromatic amines using irmof3pirucl3 with cage type poriferous structure as heterogeneous. H2tpp organocatalysis in mild and highly regioselective. Depending on the substitution pattern, the reaction proceeds either in a. Regioselective ring opening of epoxides by nucleophiles. A chairlike sixmembered transition state with minimized 1,3diaxial interactions explains the relative stereoselectivity of the cyclization reaction. A recent study has been directed to the design of metalfree lewis pair catalysts for ringopening alternating copolymerization roap reactions to enhance both activity and selectivity. Diastereoselective desymmetrization of pquinamines through. Ethyleneimine generated in situ under basic conditions from. Reading mode i recently got an email from a student asking about the best way of rationalising epoxide ring opening using some form of molecule orbitals. Highly facile biomimetic regioselective ring opening of epoxides to halohydrins in the presence of. Kiasat, maryam zayadi, mehdi fallah mehrjardi chemistry department, college of science, shahid chamran university, ahvaz 6574. If the epoxide is asymmetric, the structure of the product will vary.
While the simplest types of organic baseslewis bases for example. Epoxides are versatile intermediates in organic synthesis, but have rarely been employed in crosscoupling reactions. For ring opening epichlorohydrin with methanol, the catalytic activity shows a strong dependence on the type of support and lewis acidic species used. The key challenge for this reaction is selectivity. Catalytic regioselective epoxide ring opening with phenol. Regioselective ring opening of amino epoxides with. The ring opening reaction is regioselective with nucleophile incorporation at the less hindered carbon atom for alkylsubstituted epoxides, and at the benzylic carbon atom for aryl derivatives. Regioselective ring opening of epoxides by chelated amino acid esters enolates uli kazmaier and ameer f. For terminal epoxides, the regioselectivity of the reaction depends upon the cocatalyst employed. Opening of epoxides acidic versus basic conditions.
Reactions of epoxides ringopening chemistry libretexts. Page 9 conclusions in conclusion we could show that chelated enolates of amino acids and peptides are suitable nucleophiles for the regioselective ring opening of epoxides. Letter environmentally benign and highly regioselective ring opening of epoxides accelerated by ultrasound irradiation mohamed mahmoud nasefa,b, masoumeh zakeria, jahanbakhsh asadic, ebrahim abouzarilotfa,b, arshad ahmada and reihaneh malakootid ainstitute of hydrogen energy, universiti teknologi malaysia, 54100, kuala lumpur, malaysia. Pdf regioselective ring opening of epoxides by chelated. Regioselective ring openings of epoxides are useful and versatile methods for the construction of functionalized, enantio andor diasteromerically enriched organic compounds. Regioselective ring opening of epoxides using nh 4scnsilica sulfuric acid. Pdf regioselective ring opening of epoxides with thiols. Ceriumiii chloride promoted highly regioselective ring. Introduction of an effective and economical heterogeneous. Abstract regioselective epoxides ring opening with aromatic amines using boric acid and glycerol in water as a green media have been investigated. I am getting ready to teach epoxide ring opening reactions, and i noticed that my textbook has something different to say about the regioselectivity of acidcatalyzed ring opening than what i learned. Each synthesis is accomplished in eight steps starting from dquinic acid. The reaction is highly regioselective and afforded the corresponding products in good to excellent yields under mild and neutral reaction conditions.
Volume 43, issue 39, 23 september 2002, pages 70837086. How to predict the regioselectivity of epoxide ring opening. May 14, 2014 to the best of our knowledge, this type of reaction utilizing nonterminal epoxides as precursors remains elusive. A convenient and efficient synthesis of 1,2azidoalcohols and 1,2azidoamines has been achieved by ring opening of epoxides and aziridines using ceriumiii chloride and sodium azide in acetonitrile. Epoxide ring opening with alcohols using heterogeneous. Regioselective ring opening of enantiomerically enriched. Out of the various alcohols tested for ring opening of styrene oxide, methanol was found to be the most reactive in terms of percentage conversion and reactivity. Epoxide ring opening with alcohols using heterogeneous lewis. The nonenzymatic ringopening reactions of epoxides provide a nice overview of many of the concepts we have seen already in this chapter. High reactivity with various nucleophiles leads to high regioselective and transstereospecific ring opening products. I am getting ready to teach epoxide ringopening reactions, and i noticed that my textbook has something different to say about the regioselectivity of acidcatalyzed ringopening than what i learned. Regioselective ring opening of epoxides by chelated amino. Tungstencatalyzed regioselective and stereospecific ring. Jun 19, 2012 the regioselective ring opening of terminal epoxides using phenolic nucleophiles is examined using dimethylaminopyridine dmap as a soluble catalyst and solid catalysts based on silica, polymer, and magnetic nanoparticle solids functionalized with dmap analogues.
Metalorganic frameworks as efficient heterogeneous. Page 46 general papers arkivoc 2008 xi 4655 regioselective ring opening of epoxides with thiols in water chinmoy mukherjee,a gour hari maiti,b and anup kumar misraa amedicinal and process chemistry division, central drug research institute, chattar manzil palace, lucknow 226001, up, india bdepartment of chemistry, jadavpur university, jadavpur, kolkata700032, india email. Efficient syntheses of four aminocyclitols are reported. Metalorganic frameworks as efficient heterogeneous catalysts for the regioselective ring opening of epoxides amarajothi dhakshinamoorthy dr. A synthetically useful regioselective epoxide ringopening procedure. I recently got an email from a student asking about the best way of rationalising epoxide ring opening using some form of molecule orbitals.
Diastereoselective desymmetrization of pquinamines. Regioselectivity in the ring opening of epoxides for the. The reaction of alcohols with epoxides in the presence of boron trifluoride etherate has been investigated and found to proceed with variable regioselectivity depending on the substituents attached to the oxirane ring. When compounds 1 and 2 were treated with sodium azide in dmf under reflux conditions, they underwent a highly regioselective opening at the c4 position to afford 3 and 4, respectively scheme 1. A mechanism to explain this transformation is proposed. Catalystfree regioselective ring opening of epoxides with. Opening of epoxides with thiophenols in ionic liquids without the use of any catalyst. A highly diastereoselective desymmetrization of pquinamines via regioselective ring opening of epoxides and aziridines under mild conditions has been developed. Fully alternating and regioselective ring opening copolymerization of phthalic anhydride with epoxides using highly active metalfree lewis pairs as a catalyst a. Regioselective ring opening of aliphatic and aromatic epoxides with nitrogen heterocycles such as indoles and imidazoles was accelerated using an ultrasonic technique as a green approach.