5472-27-5Relevant academic research and scientific papers
Samarium-based Grignard-type addition of organohalides to carbonyl compounds under catalysis of CuI
Liu, Chen,Liu, Yongjun,Qi, Yan,Song, Bin,Wang, Liang,Xiao, Shuhuan
supporting information, p. 6169 - 6172 (2021/06/30)
Grignard-type additions were readily achieved under the mediation of CuI (10 mol%) and samarium (2 equiv.) by employing various organohalides,e.g.benzyl, aryl, heterocyclic and aliphatic halides (Cl, Br or I), and diverse carbonyl compounds (e.g.carbonic esters, carboxylic esters, acid anhydrides, acyl chlorides, ketones, aldehydes, propylene epoxides and formamides) to afford alcohols, ketones and aldehydes, respectively, with high efficiency and chemoselectivity, in which the organosamarium intermediate might be involved.
Development of a Scalable Lanthanide Halide/Quaternary Ammonium Salt System for the Nucleophilic Addition of Grignard Reagents to Carbonyl Groups and Application to the Synthesis of a Remdesivir Intermediate
Brak, Katrien,Bremner, W. Stacy,Brown, Angela M.,Chtchemelinine, Andrei,Heumann, Lars,Kerschen, James A.,Stevens, Andrew C.,Subotkowski, Witold,Vieira, Tiago,Wolfe, Lydia C.,Xu, Boran,Yu, Chia-Yun
, (2021/08/30)
This manuscript describes the development and implementation of a scalable additive system, consisting of a lanthanide salt and a solubilizing quaternary ammonium salt, to improve the yield and robustness of the addition of an organomagnesium reagent to a
LaCl3·2LiCl-catalyzed addition of Grignard reagents to ketones
Metzger, Albrecht,Gavryushin, Andrei,Knochel, Paul
experimental part, p. 1433 - 1436 (2009/10/17)
The addition of Grignard reagents to ketones using substoichiometric amounts of LaCl3·2LiCl was studied. Catalytic amounts of LaCl3·2LiCl (30 mol%) provide, in most cases, yields similar to those obtained using a stoichiometric amoun
Modern Friedel-Crafts chemistry. Part-29. Cyclialkylation of some triphenylated propane, butane and pentane substrates to diphenylated indans under Friedel-Crafts conditions
Khalaf, Ali A.,Awad, Ibrahim M.,El-Emary, Talaat I.,Abd El-Aal, Hassan A. K.
experimental part, p. 300 - 305 (2009/06/25)
Reactions under Friedel-Crafts cyclialkylation conditions produced : isomeric 1,2-diphenylindans from 1,2,3-triphenyl-(1- or 2-)propanol and 1-chloro-2,3,3-triphenylpropane, trans-2-benzyl-1-phenylindan from 2-benzyl-1,3-diphenyl-2-propanol, isomeric 1-me
Some uses of mischmetall in organic synthesis
Lannou, Marie-Isabelle,Hélion, Florence,Namy, Jean-Louis
, p. 10551 - 10565 (2007/10/03)
Mischmetall, an alloy of the light lanthanides, has been used in a variety of organic reactions, either as a coreductant in samarium(II)-mediated reactions (Barbier and Grignard-type reactions, pinacolic coupling reactions) or as the promoter of Reformatsky-type reactions. It has been also employed as the starting material for easy syntheses of lanthanide trihalides, the reactivity of which has been explored in Imamoto and Luche-Fukuzawa reactions and in Mukaiyama aldol reactions.
Barbier/Grignard-type allylation or benzylation mediated by the mischmetall/SmI2(cat.) system
Di Scala, Aurore,Garbacia, Stefania,Helion, Florence,Lannou, Marie-Isabelle,Namy, Jean-Louis
, p. 2989 - 2995 (2007/10/03)
Barbier- and Grignard-type allylation and benzylation have been achieved by the use of samarium diiodide in catalytic amounts together with mischmetall (an alloy of the light lanthanides) as a coreductant. Plausible catalytic schemes are proposed. In addition, organocerium and -lanthanum reagents have been obtained from samarium diiodide catalysed reactions between organic halides and cerium or lanthanum metal, giving a new route to organolanthanoid compounds. It also appears that trivalent benzyl and allyl organometallic compounds of cerium and lanthanum are much more stable than the corresponding samarium ones. Wiley-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002.
Reactions of unsaturated azides, 12[≠] azido-1,2,3-triphenylpropenes of varying stabilities: A corrigendum of structure assignment
Banert, Klaus,Hagedorn, Manfred,Liedtke, Christine,Melzer, Antje,Schoeffler, Claudia
, p. 257 - 267 (2007/10/03)
A reinvestigation of the reaction between 2,3-diphenyl-2-H-azirine (1) and phenyldiazomethane (2) has shown that a literature report has to be corrected since no vinyl azide 4 but rather the allylic compound 3-azido- 1,2,3-triphenyl-1-propene (3) is produced. This stable substance, which can also be prepared by substitution reactions of allylic bromide (E)-10 or from alcohol (E)-11, may be separated into its geometrical isomers (E)-3 and (Z)- 3, although these equilibrate through rapid [3,3] sigmatropic migration of the azido group. Attempts to synthesize 4 by dehydration of azido alcohols 7 using methanesulfonyl chloride and sulfur dioxide or by elimination of hydrogen chloride from azides 15 led only to 3 and 2-benzyl-2,3-diphenyl-2H- azirine (14). This heterocycle, which can also be prepared by Neber rearrangement, has been found to be the thermal and photochemical decomposition product of the unstable vinyl azides 4. However, dehydrations of 7 using thionyl chloride at low temperature have led to the first isolation of 1-azido-1,2,3-triphenyl-1-propenes (4). Starting with 3 and various other allylic azides, rearrangement reactions involving sigmatropic shift of the azido group or photochemical cis-trans isomerization have been investigated, as have base-catalyzed (prototropic) rearrangements to give vinyl azides.
New transition-state models and kinetics of elimination reactions of tertiary alcohols over aluminum oxide
Dabbagh,Salehi, J. Mohammad
, p. 7619 - 7627 (2007/10/03)
A new transition-state model was developed in order to justify the anti intramolecular E2 elimination with cis (Z)-preference over pure alumina and interinolecular E2 elimination with trans (E)-preference over doped alumina. The reactions of model compounds 1,2,3-triphenyl-2-propanol (1), 1,2-diphenyl-2-propanol (2), and 3,3,3-trideuterio-1,2-diphenyl-2-propanol (3) with aluminum oxides with a pH range of 4.5-9.5 and thorium oxide in the temperature range of 200-350 °C in 2-hexanol have been investigated. Over acidic alumina (pH = 4.5 ±0.5), the ratio of E-isomer to Z-isomer (E/Z ? 2) for 2 was found to remain unchanged in this temperature range. At 300 °C, however, Saytzeff elimination favored Hofmann. Over pure alumina the E/Z ratio was equal to 0.650 (2-alkene/1-alkene = 0.750). At equilibrium, the E/Z ratio for 2 was equal to 4.5 with the formation of trace amounts of Hofmann adducts. The ratio of Saytzeff to Hofmann elimination was found to be pH independent. Any decrease in pH caused a slight increase in the E/Z ratio. The average primary kinetic isotope effect (kH/kD) for elimination at 230 °C was equal to 3.775 ± 0.227. The ratio of E/Z over thorium oxide at 300 and 350 °C was similar to that of aluminum oxide at 300 °C, but the Saytzeff elimination was surprisingly favored over Hofmann! The energy of activation (Ea), entropy of activation (AS?), selectivity, isotope effect (kH/kD), and semiempirical calculation (AM1) all agreed with concerted E2 elimination.
A new method of synthesizing deoxybenzoins from 1,3-dimethyl-2-(α- benzyloxybenzyl)imidazolium and 1,3-dimethyl-2-(α- benzyloxybenzyl)benzimidazolium iodides based on Wittig-type rearrangement
Miyashita, Akira,Matsuoka, Yoshiyuki,Suzuki, Yumiko,Iwamoto, Ken-Ichi,Higashino, Takeo
, p. 1235 - 1242 (2007/10/03)
The treatment of 1,3-dimethyl-2-(α-benzyloxybenzyl)benzimidazolium iodides 1 with a base gave deoxybenzoins 2 in moderate yields. Sodium hydride (NaH), potassium carbonate (K2CO3), and cesium carbonate (Cs2CO3) were effective bases in this reaction. Deoxybenzoins 2 were produced through rearrangement of the benzyl group followed by expulsion of the 1,3- dimethylbenzimidazolium ylide (A). The rearrangement proceeds in a way similar to Wittig rearrangement. Deoxybenzoins 2 were also formed in good yields from 1,3-dimethyl-2-(α-benzyloxybenzyl)imidazolium iodides 4 upon similar treatment. However, the quaternary salts having a thiazolium moiety 5a and a pyridinium moiety 6a failed to produce deoxybenzoin (2a).
Primary and Secondary Kinetic Isotope Effects in the Decomposition of a Tertiary Alkoxide
Ibrahim, Sani,Msayib, Kadhum J.,Watt, C. Ian F.,Wilson, John M.
, p. 1703 - 1714 (2007/10/02)
Kinetic isotope effects have been determined for the elimination of toluene from the alkoxide of 1,2,3-triphenylpropan-2-ol (1a).In DMSO, the rate measurements on 1a and 1,2,3-triphenylpropanol (1b) at 30 deg C give kH4/kC4/
