- Visible-light-induced acetalization of aldehydes with alcohols
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In this work, we have achieved a simple and general method for acetalization of aldehydes by means of a photochemical reaction under low-energy visible light irradiation. A broad range of aromatic, heteroaromatic, and aliphatic aldehydes have been protected under neutral conditions in good to excellent yields using a catalytic amount of Eosin Y as the photocatalyst. Our visible light mediated acetalization strategies are successful for more challenging acid-sensitive aldehydes and sterically hindered aldehydes. Notably, this protocol is chemoselective to aldehydes, while ketones remain intact.
- Yi, Hong,Niu, Linbin,Wang, Shengchun,Liu, Tianyi,Singh, Atul K.,Lei, Aiwen
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supporting information
p. 122 - 125
(2017/11/27)
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- Co-catalysis of a bi-functional ligand containing phosphine and Lewis acidic phosphonium for hydroformylation-acetalization of olefins
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A novel ionic bi-functional ligand of L2 containing a phosphine and a Lewis acidic phosphonium with I- as the counter-anion was prepared and fully characterized. The molecular structure indicated that the bi-functionalities in L2 were well retained without the incompatibility problem for quenching of the acidity of the phosphonium cation by the Lewis basic phosphine fragment or the anionic I- when the incorporated phosphine fragment and the Lewis acidic phosphonium were strictly located in the confined cis-positions. The co-catalysis over L2-Rh(acac)(CO)2 in the ways of synergetic catalysis and sequential catalysis was successfully fulfilled for one-pot hydroformylation-acetalization, which proved not to be the result of the simple mixture of the mono-phosphine (L4) and the phosphonium salt (L4′). In L2, the phosphonium not only acted as a Lewis acid organocatalyst to drive the sequential acetalization of aldehydes, but also contributed to the synergetic catalysis for the preceding hydroformylation through stabilizing the Rh-acyl intermediate with the phosphine cooperatively. The L2-Rh(acac)(CO)2 system is also generally applied to hydroformylation-acetalization of a wide range of olefins in different alcohols. Advantageously, as an ionic phosphonium-based ligand, L2 could be recycled for 7 runs with Rh(acac)(CO)2 together in RTIL of [Bmim]BF4 without obvious activity loss or metal leaching.
- Li, Yong-Qi,Wang, Peng,Liu, Huan,Lu, Yong,Zhao, Xiao-Li,Liu, Ye
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p. 1798 - 1806
(2016/04/01)
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- Formation of acetals under rhodium-catalyzed hydroformylation conditions in alcohols
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Hydroformylation of terminal alkenes in alcohol solvents leads to the selective formation of the corresponding acetals. The Xantphos ligand gave the best results as well as acetal selectivities higher than 99% and linear/branched ratios of up to 52 were obtained. The scope of the reaction was studied. Acetals were found to be unreactive under hydroaminomethylation conditions. Copyright
- Diebolt, Olivier,Cruzeuil, Clement,Mueller, Christian,Vogt, Dieter
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supporting information; experimental part
p. 670 - 677
(2012/04/23)
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- A mild, room-temperature protection of ketones and aldehydes as 1,3-dioxolanes under basic conditions
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Protection of ketones or aldehydes as 1,3-dioxolane derivatives proceeds within minutes at room temperature in the presence of N- hydroxybenzenesulfonamide, its O-benzyl derivative, or the tosyl analogue, in the absence of strong protonic acids, and in the presence of base (Et). Acid-sensitive groups such as O-THP, O-TBS, or N-Boc are unaffected. Copyright
- Hassner, Alfred,Bandi, Chennakesava Reddy,Panchgalle, Sharad
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p. 2773 - 2776
(2013/02/21)
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- Acetalization of carbonyl compounds catalyzed by bismuth triflate under solvent-free conditions
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Carbonyl compounds were converted to the corresponding 1,3-dioxolanes and 1,3-dioxanes with ethylene glycol and 1,3-propandiol in the presence of bismuth triflate under solvent-free conditions. In addition, high chemoselective protection of aldehydes in the presence of ketones has been achieved.
- Aliyan, Hamid,Fazaeli, Razieh,Massah, Ahmad Reza,Momeni, Ahmad Reza,Naghash, Hamid Javaherian,Moeinifard, Behzad
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experimental part
p. 873 - 876
(2012/04/05)
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- Highly efficient and chemoselective acetalization of carbonyl compounds catalyzed by new and reusab e zirconyl triflate, zr0(0tf)2
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Various types of aromatic aldehydes were efficiently converted to their corresponding 1,3-dioxanes and 1,3-dioxolane with 1,3-propanediol and ethylene glycol, respectively, in the presence of catalytic amount of ZrO(OTf) 2 in acetonitrile at room temperature. The catalyst can be reused several times without loss of its catalytic activity. Very short reaction times, selective acetalization of aromatic aldehydes in the presence of aliphatic aldehydes and ketones, very mild reaction conditions, reusability of the catalyst, and easy workup are noteworthy advantages of this method.
- Moghadam, Majid,Mohammadpoor-Baltork, Iraj,Tangestaninejad, Shahram,Mirkhani, Valiollah,Yazdani, Parvin,Ghorjipoor, Saeedeh
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experimental part
p. 131 - 135
(2009/09/30)
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- Effective Au(III)-CuCl2-catalyzed addition of alcohols to alkenes
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Alkenes can be activated by Au(III) catalysts, and the effective addition of alcohols to alkenes can be carried out under mild conditions with Au(III), provided that catalytic amounts of CuCl2 are added, which significantly stabilize the cationic Au(III). The Royal Society of Chemistry.
- Zhang, Xin,Corma, Avelino
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p. 3080 - 3082
(2008/02/10)
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- Acidic properties of sulfonic acid-functionalized FSM-16 mesoporous silica and its catalytic efficiency for acetalization of carbonyl compounds
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Propyl-sulfonic acid-functionalized FSM-16 mesoporous silica (SO 3H-FSM) is prepared by a conventional post-modification method. For the acetalization of carbonyl compounds with ethylene glycol, SO 3H-FSM shows a higher rate and 1,3-dioxolane yield than conventional heterogeneous solid acids such as zeolites, montmorillonite K10 clay, silica-alumina, and the sulfonic resin. SO3H-FSM is stable during the reaction, with no leaching and deactivation of sulfonic acid groups, and is reusable without loss of its activity. The acidity and hydrophilicity of SO 3H-FSM are well characterized by the microcalorimetry of NH 3 adsorption, NH3-TPD, and H2O-TPD, and the result is compared with those for various aluminosilicate zeolites (HZSM5, HBEA, HY) and K10 clay. It is found that NH3-TPD is not suitable for characterizing the acidity of SO3H-FSM, because the decomposition of SO3H groups on SO3H-FSM begins above 200°C. An NH 3 adsorption microcalorimetric experiment at 150°C shows that, compared with HZSM5, SO3H-FSM has a smaller number of acid sites but has a similar number of strong acid sites with ammonia adsorption heat above 140 kJ mol-1. Comparison of the structural properties and catalytic results shows that a large pore diameter and low hydrophilicity are required to obtain high activity. Bronsted acid sites with a relatively strong acid strength are more suitable for this reaction, but the high acid concentration is not indispensable. The high activity of SO3H-FSM should be caused by the presence of the strong Bronsted acid sites in the mesopore with a relatively low hydrophilicity, where both reactants can smoothly access the acid sites.
- Shimizu, Ken-Ichi,Hayashi, Eidai,Hatamachi, Tsuyoshi,Kodama, Tatsuya,Higuchi, Tomoya,Satsuma, Atsushi,Kitayama, Yoshie
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p. 131 - 138
(2007/10/03)
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- Derivative of 2-cyclohexylpropanal and perfumery composition comprising the same
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2-Cyclohexylpropanal derivatives are disclosed. The derivatives are represented by the following formula (I): STR1 wherein P is a hydrogen atom and Q represents a group --CH=N--OH or a group --CH(OR)2, wherein each R represents a lower alkyl group or two R's together form a lower alkylene group which may have a lower alkyl substituent, or P and Q together form a group STR2 wherein R' is a lower alkyl group. The compounds possess floral, fruity, or green odors and are useful for preparing perfume compositions.
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- ALUMINA AS AN VERSATILE CATALYST FOR THE SELECTIVE ACETALIZATION OF ALDEHYDES
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Alumina was found to be an effective and convenient catalyst for acetalization of aldehydes to the corresponding 1,3-dioxoranes and 1,3-dioxanes.It can be used for selective protection of only formyl group of ketoaldehydes.
- Kamitori, Yasuhiro,Hojo, Masaru,Masuda, Ryoichi,Yoshida, Tatsushi
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p. 4767 - 4770
(2007/10/02)
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- A Simple and Efficient Conversion of Aldehyde Acetals into Esters
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The reaction of aldehydic acetals with hypochlorous acid in acetic acid-acetone afforded the corresponding esters in excellent yields.From cyclic acetals, only the corresponding hydroxyalkyl esters were obtained.Keywords - acetal; hypochlorite; hypochlorous acid; conversion; ester; hydroxyalkyl ester; regioselectivity
- Sugai, Saburo,Kodama, Takashi,Akaboshi, Sanya,Ikegami, Shiro
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