14802-06-3Relevant articles and documents
Radical-mediated aerobic oxidation of substituted styrenes and stilbenes
Aman, Hasil,Chiu, Wei-Hua,Chuang, Gary Jing,Liu, Pin-Heng
supporting information, p. 20103 - 20106 (2021/12/02)
A 2,2-azobis(isobutyronitrile)-catalyzed oxidative cleavage of alkenes with molecular oxygen as the oxidant was described. Carbonyl compounds and oxiranes were obtained in moderate yield under mild conditions. This study provided useful insights into the mechanism of aerobic oxidative cleavage of alkenes.
Synthesis of Epoxides from Alkyl Bromides and Alcohols with in Situ Generation of Dimethyl Sulfonium Ylide in DMSO Oxidations
Zhang, Zhi-Wei,Li, Hai-Bo,Li, Jin,Wang, Cui-Cui,Feng, Juan,Yang, Yi-Hua,Liu, Shouxin
, p. 537 - 547 (2020/01/02)
Direct conversion of the readily available alkyl bromides and alcohols to value-added epoxides using dimethyl sulfoxide (DMSO) under mild reaction conditions has been developed. Benzyl and allyl bromides, and activated and unactivated alcohols all proceeded smoothly to give epoxides in high to excellent yield. Dimethyl sulfide, generated by DMSO oxidations, was in situ elaborated to form the substituted dimethyl sulfonium ylide species that participates in the Corey-Chaykovsky epoxidation in a domino and one-pot fashion, respectively.
One-pot synthesis of epoxides from benzyl alcohols and aldehydes
Alfonzo, Edwin,Mendoza, Jesse W.L.,Beeler, Aaron B.
supporting information, p. 2308 - 2312 (2018/09/14)
A one-pot synthesis of epoxides from commercially available benzyl alcohols and aldehydes is described. The reaction proceeds through in situ generation of sulfonium salts from benzyl alcohols and their subsequent deprotonation for use in Corey–Chaykovsky epoxidation of aldehydes. The generality of the method is exemplified by the synthesis of 34 epoxides that were made from an array of electronically and sterically varied alcohols and aldehydes.
Continuous Flow Synthesis and Purification of Aryldiazomethanes through Hydrazone Fragmentation
Lévesque, éric,Laporte, Simon T.,Charette, André B.
, p. 837 - 841 (2017/01/14)
Electron-rich diazo compounds, such as aryldiazomethanes, are powerful reagents for the synthesis of complex structures, but the risks associated with their toxicity and instability often limit their use. Flow chemistry techniques make these issues avoidable, as the hazardous intermediate can be used as it is produced, avoiding accumulation and handling. Unfortunately, the produced stream is often contaminated with other reagents and by-products, making it incompatible with many applications, especially in catalysis. Herein is reported a metal-free continuous flow method for the production of aryldiazomethane solutions in a non-coordinating solvent from easily prepared, bench-stable sulfonylhydrazones. All by-products are removed by an in-line aqueous wash, leaving a clean, base-free diazo stream. Three successful sensitive metal-catalyzed transformations demonstrated the value of the method.
Benzylic Ammonium Ylide Mediated Epoxidations
Roiser, Lukas,Robiette, Rapha?l,Waser, Mario
, p. 1963 - 1968 (2016/08/10)
A high yielding synthesis of stilbene oxides using ammonium ylides has been developed. It turned out that the amine leaving group plays a crucial role as trimethylamine gives higher yields than DABCO or quinuclidine. The amine group also influences the diastereoselectivity, and detailed DFT calculations to understand the key parameters of these reactions have been carried out.
The B(C6F5)3-Catalyzed Tandem Meinwald Rearrangement-Reductive Amination
Tiddens, Martine R.,Klein Gebbink, Robertus J. M.,Otte, Matthias
supporting information, p. 3714 - 3717 (2016/08/16)
A system of three coupled catalytic cycles enabling the one-pot transformation of epoxides to amines via Meinwald rearrangement, imine condensation, and imine reduction is described. This assisted tandem catalysis is catalyzed by B(C6F5)3 resulting in the first tandem Meinwald rearrangement-reductive amination protocol. The reaction proceeds in nondried solvents and yields β-functionalized amines. In particular, β-diarylamines are obtained in high yields.
A mild access to chiral syn 1,2-diaryl glycols by stereoselective ring opening of ortho substituted trans 2,3-diaryl-oxiranes using Amberlyst 15 in H2O/THF system
Lupattelli, Paolo,Chiummiento, Lucia,Funicello, Maria,Tramutola, Francesco,Marmo, Antonella,Gliubizzi, Natascia,Tofani, Daniela
supporting information, p. 5662 - 5668 (2015/08/03)
Amberlyst 15 was an efficient and green catalyst for the reaction of 2,3-diaryloxiranes with H2O in organic co-solvent to prepare glycols in high yield. Ortho substituted trans 2,3-diaryloxiranes afforded the corresponding syn glycols stereo- and enantiospecifically. Stereoselectivity appeared related to the coordination ability of the substituents, irrespective of their electronic properties. Indeed o-OCH3 and o-OBn substituted syn glycols were obtained in high stereochemical ratios (6/1 and 10/1, respectively), and o-OTIPS and o-NO2 substituted ones were obtained as exclusive products, with the same ee of the parent epoxides.
Catalytic, regioselective, and green methods for rearrangement of 1,2-diaryl epoxides to carbonyl compounds employing metallic triflates, Br?nsted-acidic ionic liquids (ILs), and IL/microwave; Experimental and computational substituent effect study on aryl versus hydrogen migration
Jamalian, Arezu,Rathman, Benjamin,Borosky, Gabriela L.,Laali, Kenneth K.
, p. 1 - 11 (2014/11/08)
The Lewis-acid catalyzed rearrangement of parent trans-stilbene oxide 1 was studied with M(OTf)3/DCM and M(OTf)3/[BMIM][BF 4] (M = Bi, Al, Ga, Sc, and Yb; [BMIM] = butylmethylimidazolium) and Zn(NTf2)2, and with Bi(OTf)3/[BMIM][X] (X = NTf2, OTf, PF6, and BF4), employing 5 mol% of catalyst. Selective formation of 2,2-dipheylacetaldehyde 2 (phenyl migration product) was observed in all cases, with Bi(OTf)3 proving most efficient. The rearrangement of 1 was also effected in [BMIM][X] (X = NTf 2, OTf, PF6, and BF4) without an added catalyst under microwave MW irradiation, and X = PF6 gave the highest yield and selectivity. Efficient and selective rearrangement of 1-2 was also observed with 0.1-0.3 equiv. of [BMIM(SO3H)][OTf] in DCM and in [BMIM][X]. A substituent effect study was performed with a series of singly substituted 1,2-diphenyl oxiranes (with X = OMe, Me, F, CN, and NO2) with 5 mol% Bi(OTf)3 in DCM and in [BMIM][NTf2]. Notable formation of ketones was observed with the NO2 and CN derivatives. Competing formation of ketones was also observed in [BMIM][PF6] under MW and under Br?nsted acid catalysis with [BMIM(SO3H)][OTf] in DCM and in [BMIM][NTf2]. The aryl versus H migration was studied computationally by DFT and MP2 methods and by including solvation effects (IEFPCM).
Catalytic, regioselective, and green methods for rearrangement of 1,2-diaryl epoxides to carbonyl compounds employing metallic triflates, Br?nsted-acidic ionic liquids (ILs), and IL/microwave; experimental and computational substituent effect study on aryl versus hydrogen migration
Jamalian, Arezu,Rathman, Benjamin,Borosky, Gabriela L.,Laali, Kenneth K.
, p. 1 - 11 (2015/09/28)
The Lewis-acid catalyzed rearrangement of parent trans-stilbene oxide 1 was studied with M(OTf)3/DCM and M(OTf)3/[BMIM][BF4] (M = Bi, Al, Ga, Sc, and Yb; [BMIM] = butylmethylimidazolium) and Zn(NTf2)2, and with Bi(OTf)3/[BMIM][X] (X = NTf2, OTf, PF6, and BF4), employing 5 mol% of catalyst. Selective formation of 2,2-dipheylacetaldehyde 2 (phenyl migration product) was observed in all cases, with Bi(OTf)3 proving most efficient. The rearrangement of 1 was also effected in [BMIM][X] (X = NTf2, OTf, PF6, and BF4) without an added catalyst under microwave MW irradiation, and X = PF6 gave the highest yield and selectivity. Efficient and selective rearrangement of 1-2 was also observed with 0.1-0.3equiv. of [BMIM(SO3H)][OTf] in DCM and in [BMIM][X]. A substituent effect study was performed with a series of singly substituted 1,2-diphenyl oxiranes (with X = OMe, Me, F, CN, and NO2) with 5mol% Bi(OTf)3 in DCM and in [BMIM][NTf2]. Notable formation of ketones was observed with the NO2 and CN derivatives. Competing formation of ketones was also observed in [BMIM][PF6] under MW and under Br?nsted acid catalysis with [BMIM(SO3H)][OTf] in DCM and in [BMIM][NTf2]. The aryl versus H migration was studied computationally by DFT and MP2 methods and by including solvation effects (IEFPCM).
An effective dual copper-and sulfide-catalytic system for the epoxidation of aldehydes with phenyldiazomethane
Pereira, Ana,Martín, Carmen,Maya, Celia,Belderrain, Tomás R.,Pérez, Pedro J.
supporting information, p. 2942 - 2951 (2014/03/21)
Epoxides have been obtained from alde-hydes and phenyldiazomethane using catalytic amounts of both the copper homoscorpionate com-plexes Tp xCuL (Tpx = homoscorpionate ligand; L = acetonitrile or tetrahydrofuran, THF) and dimethyl sulfide (SMe2) in high yields and diasteroselectivities, and with activities higher (TOF = 46 h-1) than those already known with rhodium-or copper-based cata-lysts. Among the copper(I) homoscorpionate com-plexes tested, TpBr3Cu(NCCH 3) showed the highest catalytic activity under mild conditions. The catalytic activity is controlled by electronic effects induced by the Tp x ligand as well as by the stability of the TpxCu(SR 2) adducts. Indeed, in the case of TpMs as ligand, the TpMsCu(THT) (THT = tetrahydrothio-phene) and Tp MsCu(SMe2) species could be isolated as very stable crystalline solids, the molecular struc-ture of the former being confirmed by single-crystal X-ray diffraction analysis. The in situ generation of PhCHN 2 from benzaldehyde tosylhydrazone sodium salt at 60 °C in methyl tert-butyl ether as solvent and TpMsCu(THF) as the catalyst also showed high cata-lytic activities, improving those already reported with copper-based catalysts.
