Pdf thiolysis of alkyland aryl1, 2epoxides in water catalyzed. The regioselectivity of the nucleophilic attack is markedly influenced going from ph 9. Commercially available zincii perchlorate hexahydrate znclo426h2o was found to be a new and highly efficient catalyst for opening of epoxide rings by amines affording 2amino alcohols in high yields under solventfree conditions and with excellent chemo, regio, and stereoselectivities. The catalyst is recoverable and can be used in next reactions. Chain end modification of low molecular weight, raftprepared polystyrene and polyn,ndiethylacrylamide by reaction with a range of small molecule epoxides is described. Although, the opening of epoxides with thiols has been reported in water using indium chloride or zncl2 or naoh.
A new approach for the synthesis of thiazolopyridinium ionic liquids. Lithium binol phosphate catalyzed desymmetrization of meso. For unsymmetrical epoxides, the regioselectivity was influenced by the electronic and steric. An easy access to hydroxy sulfides and benzoxathiepinones in solvent.
The indiumbipyridinecatalyzed, enantioselective ringopening of meso epoxides with aliphatic and aromatic thiols furnished 1,2mercapto alcohols in good yields and excellent enantioselectivities. Antilla department of chemistry, university of south florida, 4202 east fowler avenue, tampa, florida 33620, united states. Prompted by these reports, we were interested to perform the thiolysis of epoxides using water as a solvent avoiding the use of a catalyst and organic solvents. Two different routes are examinedinitial dithioester endgroup cleavage yielding the thiolterminated polymer followed by catalytic thiolysis of the oxiranes and a onepot procedure involving hydride. Lowe centre for advanced macromolecular design camd, school of chemical engineering, university of new south wales, kensington 2052, sydney, australia. The process is solventfree and takes place efficiently at roomtemperature. Azidolysis, hydrolysis, iodolysis and thiolysis are the reactions mainly investigated. Thiolysis of alkyl and aryl1,2 epoxides was investigated under solventfree conditions in the presence of lewis and bronsted acid and base catalysts incl3, ptsoh, nbu3p, k2co3. A simple, rapid, atom economy and highly efficient procedure has been developed for thiolysis of epoxides by aromatic and aliphatic thiols under solventfree conditions. Groups that are trans on the alkene will end up trans on the epoxide product. Wastefree thiolysis of epoxide in water with high yield.
Recyclable superparamagnetic fe3o4 nanoparticles for. The important features of this methodology are broad substrates scope, high yielding, reasonably rapid reaction rate, high regioselectivity and no requirement of. Hydrolysis rates of epoxides are accelerated by structural features that stabilize the incipient carbocation and therefore favour an sn1 reaction, such as in the case of allylic or benzylic epoxides. The aqueous medium and the catalyst were recovered and reused in various runs without affecting the. Thiolysis of 1,2epoxides represents an effective and convenient entry to. Five mol% of catalyst was sufficient and the best results were obtained by using incl 3 and k 2 co 3. The aqueous medium and the catalyst were recovered and reused in various runs without affecting the efficiency of the process. A convenient, economical, and practical protocol for boraxcatalyzed thiolysis of 1,2 epoxides in aqueous medium has been developed, which has greatly expanded the utility scope of borax in. Epoxides react very efficiently in water with several nucleophiles, and several examples in the literature report that the use of water as reaction medium is essential for realizing processes that cannot be performed alternatively in other reaction media. Zncl2 as an efficient catalyst in the thiolysis of 1,2epoxides by. Pdf regioselective ring opening of epoxides with thiols. The advanced intermediate 122 was converted to the epoxide 123, which upon thiolysis with a strategically protected cysteine, gave the regioisomeric hydroxy sulfides 124 and. The thiolysis of epoxides is the most common and best route for the synthesis. Solventfree thiolysis of epoxides under lithium perchlorate catalysis.
Thiolysis of a variety of 1,2 epoxides in water at 30 c and ph 7. Pdf magnesium chloridecatalyzed thiolysis of epoxides. Incl3catalyzed highly regioselective ring opening of. Full papers thiolysis of alkyl and aryl1,2epoxides in water catalyzed by incl3 francesco fringuelli, ferdinando pizzo, simone tortoioli, luigi vaccaro. Sustainable development requires redesigning many organic.
Keto sulfides, australian journal of chemistry on deepdyve, the largest online rental service for scholarly research with thousands of academic publications available at your fingertips. Read ionic liquid promoted regio and stereoselective thiolysis of epoxides a simple and green approach to. An efficient catalyst for ring opening of epoxides with phenol and thiophenol under solventfree conditions. Groups that are cis on the alkene will end up cis on the epoxide product. Thiolysis of a variety of 1,2epoxides in water at 30 degrees c and ph 7. Nucleophilic ring opening of 1,2epoxides in aqueous. Zncl2 5 mol% is an efficient catalyst for the thiolysis of. Zniicatalyzed thiolysis of oxiranes in water under. Solventfree ring opening of 1,2 epoxides with thiols using catalytic amounts of lithium perchlorate affords high yields of. Incl3catalyzed highly regioselective ring opening of epoxides with thiols article in cheminform 343 january 2003 with 56 reads how we measure reads.
A high regioselectivity in favor of nucleophilic attack at the benzylic carbon atom of aromatic epoxides, such as styrene oxide, is observed. Organic chemists have usually performed thiolysis in organic solvents thf. Thiolysis of epoxides offers an efficient and simple synthetic approach to access \\beta \ hydroxy sulfides which are valuable scaffold in the synthesis of various important molecules in. The ph of the reaction medium controls the reactivity and regioselectivity of. Nucleophilic attack of the thiols occurs regioselectively at the sterically less hindered side of the epoxides. Thiolysis of epoxides offers an efficient and simple synthetic approach to access \\beta \hydroxy sulfides which are valuable scaffold in the synthesis of various important molecules in medicinal chemistry. A mild and convenient ring opening of epoxides with thiophenol and its derivatives takes place at room temperature in the presence of magnesium chloride as. Onepot synthesis of benzoe1,4oxathiepin5ones under. The geometry of the alkene is preserved in the product recall the cyclopropanation of alkenes, ch. Benzoe1,4oxathiepin5ones 4 have been easily prepared in a regio and diasteroselective manner and in satisfactory yields. O o relative rate 6 x 104 1 in the absence of structural features that stabilize carbocation intermediates, the sn2 reaction will. It was efficiently catalyzed by a chiral dy iii n,ndioxide complex through a thiolysis elimination sequence. Incl 3 showed a very high efficiency in catalyzing this process at ph 4.
An efficient catalyst for ring opening of epoxides with. Hydroxy sulfides and their syntheses beilstein journals. Superparamagnetic fe 3o 4 nanoparticles cause rapid thiolysis of epoxides. Saeed abaee, vahid hamidi chemistry and chemical engineering research center of iran, p.
Nucleophilic ring opening of 1,2epoxides in aqueous medium. This remote stereocontrol strategy provides facile access to synthetically versatile cyclopentene. Thiolysis of 1,2epoxides by thiophenol catalyzed under. Pdf epoxide ring opening with thioacetic acid and thiobenzoic acid. Tetrathiomolybdate assisted epoxide ring opening with.
An environmentally benign and efficient process for the preparation of. An unprecedented asymmetric desymmetrization of meso. Thiolysis of a variety of 1,2 epoxides in water at 30 degrees c and ph 7. Author links open overlay panel hongfei lu a juntao zhou a helong cheng a leilei sun a feifei yang a runze wu a yuhua gao a zhibin luo b.
Under solventfree conditions, thiosalicylic acid 2 efficiently selfpromotes the thiolysis of 1,2 epoxides 1, antistereoselectively and generally totally. Recent trends in ring opening of epoxides with sulfur. Indiumbipyridinecatalyzed, enantioselective thiolysis of. The reaction was compatible with a variety of epoxide substrates such as. Lithium binol phosphate catalyzed desymmetrization of meso epoxides with aromatic thiols gajendrasingh ingle, michael g.
In principle, the products can be obtained by direct attack at c1 or c2 of epoxide ring or by conjugative addition resulting from an attack at c6. This strategy has been utilized effectively in the construction of thiabicylo3. Regioselective ring opening of epoxides with thiols in water. Thiolysis of 1, 2 epoxides by thiophenol catalyzed under solventfree conditions. Recently, a number of reports appeared for the thiamichael8 and azamichael9 reaction and ring opening of epoxides with amines10 in water without using any catalyst.
Nbs as a powerful catalyst for the synthesis ofhydroxysulphides with thiolysis of epoxides under mild reaction conditions amin rostamia and hadi jafarib adepartment of chemistry, faculty of science, university of kurdistan, sanandaj 6617715143, iran. Boraxcatalyzed thiolysis of 1,2epoxides in aqueous medium. The ringopening reactions of different epoxides with several diaryl disul. The thiolysis of epoxides is the most common and best route for the synthesis of. Zincii perchlorate hexahydrate catalyzed opening of. Hydrolysis of 1,2 epoxides of polycyclic substrates. Reactions carried out by using benzeneoxepin 3,6deuterated indicate that the nucleophilic addition occurs only by 1,2addition. Bromodimethylsulfonium bromidemediated thiolysis of.
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