- Ketones as electrophile in nitroaldol reaction: Synthesis of β,β-disubstituted-1,3-dinitroalkanes and allylic nitro compounds
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β,β-Disubstituted-1,3-dinitro compounds were obtained exclusively with an overall yield of 83% through a domino nitroaldol/elimination/1,4-addition process, when excess nitromethane was added to cyclohexanone or butanone using DBU (1,8-diazabicyclo[5.4.0]
- Costa, Jeronimo S.,Gomes, Alex O.,Pereira, Vera Lúcia P.,de Souza, Douglas L. F.
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p. 1575 - 1583
(2021/07/06)
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- 1,3-Difunctionalization of β-alkyl nitroalkenes via combination of Lewis base catalysis and radical oxidation
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Upon treatment with a Lewis base catalyst, β-alkyl-substituted nitroalkenes could be readily converted into allylic nitro compounds. Examples of either C-1 or C-3 functionalization methods have been reported through nitro-elimination, giving alkene products. In this work, successful 1,3-difunctionalization was achieved through a synergetic Lewis base catalysis and TBHP radical oxidation, giving vinylic alkoxyamines in good to excellent yields. This work further extended the general synthetic application of β-alkyl nitroalkenes.
- Wang, Ye,Zheng, Lei,Shi, Xiaodong,Chen, Yunfeng
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supporting information
p. 886 - 889
(2021/02/01)
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- Method for taking DAST reagent as removing reagent to synthetize conjugated nitroolefin substituted series derivative
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The invention discloses a preparation method of taking a DAST reagent as a removing reagent to synthesize a conjugated nitroolefin substituted series derivative. The preparation method comprises the following steps that a carbonyl compound (compound II) i
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Paragraph 0072-0075
(2018/12/13)
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- A One-Pot Reaction toward the Diastereoselective Synthesis of Substituted Morpholines
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The diastereoselective synthesis of various substituted morpholines has been achieved from vinyloxiranes and amino-alcohols under sequential Pd(0)-catalyzed Tsuji-Trost/Fe(III)-catalyzed heterocyclization. Using the same strategy, 2,6-, 2,5-, and 2,3-disubstituted as well as 2,5,6- and 2,3,5-trisubstituted morpholines were obtained in good to excellent yields and diastereoselectivities.
- Aubineau, Thomas,Cossy, Janine
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supporting information
p. 7419 - 7423
(2018/12/11)
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- Henry reaction catalyzed by recyclable [C4dabco]OH ionic liquid
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DABCO-based ionic liquid, 1-butyl-4-aza-1-azaniabicyclo[2.2.2]octane hydroxide, has been used as an efficient catalyst for Henry reaction of various carbonyl compounds with nitroalkanes affording very high yields within a short duration. This method is very simple, clean and avoids hazardous organic solvents. The catalyst can be easily recovered and recycled several times.
- Keithellakpam, Sanjoy,Laitonjam, Warjeet S.
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p. 110 - 113
(2016/02/26)
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- Henry reaction catalyzed by recyclable [C4dabco]OH ionic liquid
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DABCO-based ionic liquid, 1-butyl-4-aza-1-azaniabicyclo[2.2.2]octane hydroxide, has been used as an efficient catalyst for Henry reaction of various carbonyl compounds with nitroalkanes affording very high yields within a short duration. This method is very simple, clean and avoids hazardous organic solvents. The catalyst can be easily recovered and recycled several times.
- Keithellakpam, Sanjoy,Laitonjam, Warjeet S.
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p. 110 - 113
(2017/01/18)
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- RECYCLABLE CHIRAL CATALYST FOR ASYMMETRIC NITROALDOL REACTION AND PROCESS FOR THE PREPARATION THEREOF
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The present invention relates to preparation of highly efficient chiral recyclable homogeneous catalysts generated in situ by the reaction of chiral oligomeric [H4] ligands and a metal salt taken in 1:1 molar ratio for asymmetric nitroaldol reaction, wherein nitroaldol reactions of various aldehydes such as aromatic, aliphatic α,β-unsaturated aldehydes, alicyclic aldehydes and nitroalkenes were carried out to produce optically active β-nitroalcohols in high yield and with moderate to excellent enantioselectivity (ee up to >95%) in presence of a base and an optically active chiral recyclable homogeneous catalyst represented by the following formula (I).
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Paragraph 0272
(2016/01/15)
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- Asymmetric organocatalytic Michael-hemiacetalization reaction: Access to chiral spiro cis-δ-lactones by in situ oxidation of spiro δ-lactols
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Asymmetric tandem Michael-hemiacetalization reaction between 1-nitromethylcycloalkanol and α,β-unsaturated aldehydes was investigated, which provided an efficient and facile synthesis for spiro cis-δ-lactones by in situ oxidation of spiro δ-lactols in goo
- Wei, Mo-Hui,Zhou, Yi-Rong,Gu, Liang-Hu,Luo, Fan,Zhang, Fang-Lin
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supporting information
p. 2546 - 2548
(2013/06/27)
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- Methylcarbonate and bicarbonate phosphonium salts as catalysts for the nitroaldol (Henry) reaction
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Phosphonium ionic liquids exchanged with bicarbonate and methylcarbonate anions (CILs) exhibit catalytic performances comparable to those of sterically hindered (non nucleophilic) organosuperbases such as DBU. At 25-50 °C, under solventless conditions, CI
- Fabris, Massimo,Noe, Marco,Perosa, Alvise,Selva, Maurizio,Ballini, Roberto
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experimental part
p. 1805 - 1811
(2012/04/17)
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- Recyclable Cu(II)-macrocyclic salen complexes catalyzed nitroaldol reaction of aldehydes: A practical strategy in the preparation of (R)-phenylephrine
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Chiral macrocyclic salen ligands 1′-3′ derived from 1R,2R-(-)-1,2-diaminocyclohexane, 1R,2R-(+)-1,2-diphenyl-1,2-diaminoethane and (R)-(+)-1,1′-binaphthyl-2,2′-diamine with trigol bis aldehyde were prepared and characterized by microanalysis, 1H NMR, UV/Vis. spectroscopy, optical rotation and mass spectroscopy. Highly enantioselective nitroaldol reaction of various aromatic and aliphatic aldehydes with nitromethane in presence of several bases were carried out in the presence of in situ generated Cu(I)/Cu(II) complexes with chiral macrocyclic salen ligands 1′-3′ at RT. Excellent yields (up to 92% with respect to the aldehyde) of β-nitroalcohols with high enantioselectivity (ee, ~95%) was achieved in case of 3-methoxy- and 4-nitrobenzaldehyde in ca. 30 h with the use of chiral macrocyclic salen ligands 3′ with CuCl2· 2H2O in presence of 2,6-lutidine as a base. Chiral macrocyclic salen catalyst 3 mediated nitroaldol process is recyclable (up to 8 cycles with no significant loss in its performance). This protocol is also used for the synthesis of enantiomerically pure (R)-phenylephrine (α1-adrenergic receptor agonist) via asymmetric nitroaldol reaction of 3-methoxybenzaldehyde in three steps.
- Kureshy, Rukhsana I.,Dangi, Balchand,Das, Anjan,Khan, Noor-Ul H.,Abdi, Sayed H.R.,Bajaj, Hari C.
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experimental part
p. 74 - 79
(2012/10/07)
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- The first report on chemoselective biguanide-catalyzed henry reaction under neat conditions
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An efficient synthetic method for direct Henry reaction catalyzed by a biguanide; namely metformin, as an organosuper-base, between a variety of aromatic and aliphatic aldehydes and nitromethane under neat conditions has been developed. Convenient procedure for removal of the catalyst, chemoselective acquiring of β-nitroalcohols as predominant products, as far as possible short reaction time with excellent conversions are advantages of the developed protocol.
- Alizadeh, Abdolhamid,Khodaei, Mohammad M.,Abdi, Gisya,KORdestani, Davood
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p. 3640 - 3644
(2013/01/16)
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- Efficient nitro-aldol reaction using SmI2: A new route to nitro alcohols under very mild conditions
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(Chemical Equation Presented) A novel method to obtain racemic 1-nitroalkan-2-ols by reaction of bromonitromethane with a variety of aldehydes and promoted by SmI2 is reported. On the basis of these results, the chiral version has also been per
- Concellon, Jose M.,Rodriguez-Solla, Humberto,Concellon, Carmen
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p. 7919 - 7922
(2007/10/03)
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- Rapid microwave-assisted Henry reaction in solvent-free processes
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The solvent-free Henry reactions of nitromethane with a series of carbonyl compounds were studied under microwave irradiation. By using different bases and Lewis acids, the solvent-free nitroaldol reaction of aldehydes were realized under microwave condition, affording the corresponding adducts with high yields. Particularly, aliphatic ketones, which were hardly carried out this reaction, could be the reaction substrates in the nitroaldol reactions by employment of 1,4-diazabicyclo[2.2.2]octane (DABCO) under a similar conditions, giving the corresponding adducts with moderate to good yields. Georg Thieme Verlag Stuttgart.
- Gan, Changsheng,Chen, Xing,Lai, Guoyin,Wang, Zhiyong
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p. 387 - 390
(2007/10/03)
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- An efficient method for the preparation of β-nitroalkanols in room temperature ionic liquids
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β-Nitroalkanols were obtained in good to high yields from carbonyl substrates and nitroalkanes in the room temperature ionic liquids using DBU as catalyst under mild reaction conditions and short reaction times.
- Qian, Weixing,Ju, Fengyang,Bao, Weiliang,Zhang, Yongmin
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p. 154 - 155
(2007/10/03)
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- Ionic liquid catalyzed Henry reactions
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The 1,1,3,3-tetramethyl guanidine (TMG)-based ionic liquid was used as a recyclable catalyst for Henry reactions to produce 2-nitroalcohols. Good yields were obtained even after 15 reactions.
- Jiang, Tao,Gao, Haixiang,Han, Buxing,Zhao, Guoying,Chang, Yanhong,Wu, Weize,Gao, Liang,Yang, Guanying
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p. 2699 - 2701
(2007/10/03)
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- 1,5,7-Triazabicyclo[4.4.0]dec-1-ene (TBD), 7-methyl-TBD (MTBD) and the polymer-supported TBD (P-TBD): Three efficient catalysts for the nitroaldol (Henry) reaction and for the addition of dialkyl phosphites to unsaturated systems
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The 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD) and its 7-methyl derivative (MTBD) have been proven to be of great synthetic utility as catalysts in the nitroaldol (Henry) reaction and for the addition of dialkyl phosphites to a variety of carbonyl compounds. The catalysts were in many cases superior to the parent tetramethylguanidine (TMG). In general the reaction proceeds in a few minutes at 0°C. The polymer-supported-TBD (P- TBD) was also proven to be an efficient promoter of the above cited nucleophilic additions. (C) 2000 Elsevier Science Ltd.
- Simoni, Daniele,Rondanin, Riccardo,Morini, Massimo,Baruchello, Riccardo,Invidiata, Francesco Paolo
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p. 1607 - 1610
(2007/10/03)
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- P(RNCH2CH2)3N: An Efficient Promoter for the Nitroaldol (Henry) Reaction
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The use of catalytic amounts of the proazaphosphatranes P(MeNCH2CH2)3N, P(i-PrNCH2CH2)3N and P(HNCH2CH2)(i-PrNCH2CH2) 2N as nonionic bases in the reaction of nitroalkanes with carbonyl compounds is reported. The reaction proceeds at room temperature in the presence of 2.2 equiv of magnesium sulfate to produce the corresponding β-nitroalkanols in generally superior yields. Aldehydes react quantitatively in 5-60 min, whereas ketones require up to 3 h to react with nitromethane and up to 7 h for the reaction of ketones with higher nitroalkanes.
- Kisanga, Philip B.,Verkade, John G.
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p. 4298 - 4303
(2007/10/03)
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- Facile synthesis of 2-nitroalkanols by tetramethylguanidine (TMG)-catalyzed addition of primary nitroalkanes to aldehydes and alicyclic ketones
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Tetramethylguanidine-catalyzed addition of primary nitroalkanes to aldehydes and alicylic ketones constitutes a practical means to perform the nitro-aldol reaction (Henry reaction). The very mild conditions employed, together with the short reaction times, make the procedure tolerant of a range of functionalities and highly versatile for the synthesis of a variety of 2-nitroalkenols.
- Simoni, Daniele,Invidiata, Francesco Paolo,Manfredini, Stefano,Ferroni, Roberto,Lampronti, Ilaria,Roberti, Marinella,Pollini, Gian Piero
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p. 2749 - 2752
(2007/10/03)
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