7417-73-4Relevant academic research and scientific papers
Zirconium-catalysed direct substitution of alcohols: enhancing the selectivity by kinetic analysis
Camaj, David,Carlsson, Robin,Dalla-Santa, Oscar,Lill, Malin,Lundberg, Helena,Margarita, Cristiana,Ramstr?m, Anja,Tu?on, Hernando,Villo, Piret
, p. 7420 - 7430 (2021/11/23)
Kinetic analysis was used as a tool for rational optimization of a catalytic, direct substitution of alcohols to enable the selective formation of unsymmetrical ethers, thioethers, and Friedel-Crafts alkylation products using a moisture-tolerant and commercially available zirconium complex (2 to 8 mol%). Operating in air and in the absence of dehydration techniques, the protocol furnished a variety of products in high yields, including glycosylated alcohols and sterically hindered ethers. In addition, the kinetic studies provided mechanistic insight into the network of parallel transformations that take place in the reaction, and helped to elucidate the nature of the operating catalyst.
Ru(ii)-Catalysed synthesis of (1 H)-isothiochromenes by oxidative coupling of benzylthioethers with internal alkynes
Urriolabeitia, Esteban P.,Ruiz, Sara
supporting information, p. 2542 - 2547 (2019/03/06)
The synthesis of 1H-isothiochromenes by oxidative coupling of benzyl(tert-butyl)thioethers with internal alkynes, catalysed by Ru(ii), has been achieved. The reaction occurs by S-directed C-H activation at the ortho position of the aryl ring, promoted by ruthenium, migratory insertion of the alkyne, 1,2-thio-Wittig rearrangement of the tert-butyl group and reductive elimination by C-S coupling between the resulting anionic sulfide and the vinylic carbon.
Benign and efficient preparation of thioethers by solvent-free S-alkylation of thiols with alkyl halides catalyzed by potassium fluoride on alumina
Nguyen, Kha Ngoc,Duus, Fritz,Luu, Thi Xuan Thi
, p. 349 - 360 (2016/06/01)
The preparation of thioethers by S-alkylation of various thiols with alkyl halides under solvent-free reaction conditions using potassium fluoride on alumina (KF/Al2O3) as a solid catalyst has been investigated in detail with respect to three different modes of reaction activation (ultrasound irradiation, microwave irradiation, and conventional heating) for obtaining maximum yield of the thioether. The importance of KF/Al2O3 as a particularly efficient catalyst was corroborated for all three modes of reaction activation, although the reaction time was found to be strongly dependent on the mode of activation. The yield of the thioethers was also found to depend on the amount of the solid catalyst relative to the equimolar amounts of the two reactants.
Indium-Catalyzed Reductive Sulfidation of Esters by Using Thiols: An Approach to the Diverse Synthesis of Sulfides
Miyazaki, Takahiro,Kasai, Shinsei,Ogiwara, Yohei,Sakai, Norio
, p. 1043 - 1049 (2016/03/01)
A new reductive preparation of unsymmetrical sulfides from esters and thiols in the presence of InI3 and either 1,1,3,3-tetramethyldisiloxane (TMDS) or PhSiH3 as the reductant was developed. This protocol was applied to not only benzoic acid esters that have a methoxy, methyl, chloro, bromo, iodo, or trifluoromethyl group on the aromatic ring but also aliphatic acid esters with either aromatic or aliphatic thiols. A reaction mechanism is proposed by using Hammett plot results and several control experiments. The reductive preparation of unsymmetrical sulfides from esters and thiols by using InI3 and either 1,1,3,3-tetramethyldisiloxane (TMDS) or PhSiH3 was developed. Several mechanistic studies support that the present transformation proceeds through O,S-and S,S-acetals as the reaction intermediates. TMDS = 1,1,3,3-tetramethyldisiloxane, R = aliphatic group.
Enantioselective synthesis of benzyl tert-butyl sulfoxides
Syed, Majid Khalil,Casey, Mike
experimental part, p. 7207 - 7214 (2012/01/16)
Enantiomerically pure benzyl sulfoxides are effective tools for the formation of new C-C bonds with control of configuration at new stereogenic centres. The reaction of enantioenriched tert-butyl tert-butanethiosulfinate with benzyllithium derivatives, ob
Enantioselective synthesis, configurational stability, and reactivity of lithium α-tert-butylsulfonyl carbanion salts
Scholz, Roland,Hellmann, Gunther,Rohs, Susanne,Oezdemir, Diana,Raabe, Gerhard,Vermeeren, Cornelia,Gais, Hans-Joachim
supporting information; experimental part, p. 4588 - 4616 (2010/10/21)
The reactions of enantiopure S-tert-butyl sulfones of the type R 1CH(R2)SO2tBu (≥99% ee) with lithiumorganyl compounds gave the corresponding chiral α-sulfonyl carbanion salts [R 1C(R2)SO2tBu]Li with ≥94% ee. The enantioselectivity of the deprotonation of the phenyl- but not dialkyl-substituted sulfones is strongly dependent on the nature of the lithiumorganyl. Because of this observation and the strong decrease in enantioselectivity in the presence of TMEDA and HMPA, we propose an intramolecular proton transfer following complexation of the sulfone by RLi. Racemization of [R1C(R2)-SO2tBu]Li follows first-order kinetics and seems to be mainly an enthalpic process with a small negative activation entropy, as revealed by polarimetric measurements at low temperatures. This is in accordance with Cα-S bond rotation as the rate-determining step. The salts [R1C(R2)SO 2tBu]Li have half-lives of racemization in the order of several hours at -105°C. The deuteriation of the salts at -105°C with CF 3CO2D proceeded with enantioselectivities of 94% ee, the magnitude of which was not significantly affected by the presence of TMEDA and HMPA. The salts also reacted with carbon-based electrophiles at low temperatures with high enantioselectivity. The conversion of R1CH(R 2)SO2tBu via [R1C(R2)SO 2tBu]Li to R1C(R2,E)SO2tBu, which involves the loss of stereogenicity at the α-stereogenic center and its reestablishment upon reaction of the chiral carbanion with electrophiles, occurred with high overall enantioselectivity. Electrophiles attack the anionic C atom of [R1C(R2)SO2tBu]Li with high selectivity on the side syn to the O atoms and anti to the tert-butyl group. The reactivity of the dialkyl-substituted salts [R1C(R 2)SO2tBu]Li (R1, R2 = alkyl) is significantly higher than that of the benzylic salts [RC(Ph)SO2tBu]Li (R = alkyl) and the HMPA-coordinated SIPs of [MeC(Ph)SO2- tBu]Li are significantly more reactive towards EtI than the corresponding O-Li contact ion pairs.
A novel approach to the practical synthesis of sulfides: An InBr 3-Et3SiH catalytic system promoted the direct reductive sulfidation of acetais with disulfides
Sakai, Norio,Moritaka, Kohei,Konakahara, Takeo
supporting information; experimental part, p. 4123 - 4127 (2009/12/09)
We have demonstrated a facile and direct synthesis of sulfide derivatives using acetais and ketals, derived, from aromatic/ conjugated, aldehydes and aromatic ketones, with disulfides and the InBr3-Et3SiH reducing system., We also succeeded in developing an unprecedented one-pot preparation of an aliphatic sulfide from a disulfide and an aliphatic acetal. (Wiley-VCH Verlag GmbH & Co. KGaA.
A novel approach for the direct conversion of alkylsulfonyl derivatives into alkylcarbonyl derivatives via tin-free radical carbonylation
Kim, Sangmo,Lim, Kyoung-Chan,Kim, Sunggak
, p. 4507 - 4509 (2008/04/01)
A novel radical approach for the direct conversion of RSO2X into RCOX in a single step is devised; the present approach is very simple, highly efficient, and minimizes formation of by-product. The Royal Society of Chemistry.
Ionic liquid as catalyst and reaction medium: A simple, convenient and green procedure for the synthesis of thioethers, thioesters and dithianes using an inexpensive ionic liquid, [pmIm]Br
Ranu, Brindaban C.,Jana, Ranjan
, p. 1811 - 1818 (2007/10/03)
An easily accessible and inexpensive room temperature ionic liquid, 1-pentyl-3-methylimidazolium bromide, [pmIm]Br efficiently catalyzes the reaction of alkyl halides or acyl halides with thiols without any solvent at room temperature leading to the synthesis of thioethers and thioesters in high yields. This reaction has also been extended for the preparation of dithianes and transthioetherification. The ionic liquid is recovered and recycled for subsequent runs.
A novel method for the stereoselective synthesis of tetralins and indanes
Appelbe, Zelda,Casey, Mike,Keaveney, Claire M.,Kelly, Cornelius J.
, p. 1404 - 1408 (2007/10/03)
Heavily-substituted 1-aryltetralins and 1-arylindanes were prepared in a highly stereoselective manner using a two-step sequence. Addition of t-butyl benzyl sulfoxides to unsaturated carbonyl compounds gave conjugate adducts with high diastereoselectivity
