- Benzoxaborole Catalyst for Site-Selective Modification of Polyols
-
The site-selective modification of polyols bearing several hydroxyl groups without the use of protecting groups remains a significant challenge in synthetic chemistry. To address this problem, novel benzoxaborole derivatives were designed as efficient catalysts for the highly site-selective and protecting-group-free modification of polyols. To identify the effective substituent groups enhancing the catalytic activity and selectivity, a series of benzoxaborole catalysts 1a–k were synthesized. In-depth analysis for the substituent effect revealed that 1i–k, bearing multiple electron-withdrawing fluoro- and trifluoromethyl groups, exhibited the greatest catalytic activity and selectivity. Moreover, 1i-catalyzed benzoylation, tosylation, benzylation, and glycosylation of various cis-1,2-diol derivatives proceeded with good yield and site-selective manner.
- Kusano, Shuhei,Miyamoto, Shoto,Matsuoka, Aki,Yamada, Yuji,Ishikawa, Ryuta,Hayashida, Osamu
-
supporting information
p. 1598 - 1602
(2020/02/11)
-
- DBN-Catalyzed Regioselective Acylation of Carbohydrates and Diols in Ethyl Acetate
-
The 1,5-diazabicyclo[4.3.0]non-5-ene (DBN)-catalyzed regioselective acylation of carbohydrates and diols in ethyl acetate has been developed. The hydroxyl groups can be selectively acylated by the corresponding anhydride in EtOAc in the presence of a catalytic amount (as low as 0.1 equiv.) of DBN at room temperature to 40 °C. This method avoids metal catalysts and toxic solvents, which makes it comparatively green and mild, and it uses less organic base compared with other selective acylation methods. Mechanism studies indicated that DBN could catalyze the selective acylation of hydroxyl moieties through a dual H-bonding interaction.
- Ren, Bo,Zhang, Mengyao,Xu, Shijie,Gan, Lu,Zhang, Li,Tang, Lin
-
supporting information
p. 4757 - 4762
(2019/07/31)
-
- An inexpensive catalyst, Fe(acac)3, for regio/site-selective acylation of diols and carbohydrates containing a 1,2-: Cis -diol
-
This work describes the [Fe(acac)3] (acac = acetylacetonate)-catalyzed, regio/site-selective acylation of 1,2- and 1,3-diols and glycosides containing a cis-vicinal diol. The iron(iii) catalysts initially formed cyclic dioxolane-type intermediates with substrates between the iron(iii) species and vicinal diols, and the efficient and selective acylation of one hydroxyl group was subsequently achieved by adding acylation reagents in the presence of diisopropylethylamine (DIPEA) under mild conditions. This reaction generally produced high selectivities and highly isolated yields with the same protection pattern as that achieved with dibutyl tinoxide-mediated schemes.
- Lv, Jian,Ge, Jian-Tao,Luo, Tao,Dong, Hai
-
supporting information
p. 1987 - 1991
(2018/05/23)
-
- Diacyl Disulfide: A Reagent for Chemoselective Acylation of Phenols Enabled by 4-(N,N-Dimethylamino)pyridine Catalysis
-
A general and excellent acylation reagent, diacyl disulfide, was uncovered for efficient ester formation enabled by DMAP (4-(N,N-dimethylamino)pyridine) catalysis. This protocol offered a promising synthetic platform on site-selective acylation of phenolic and primary aliphatic hydroxyl groups, which greatly expanded the realm of protecting group chemistry. The importance of the reagent was also reflected by its excellent moisture tolerance, high efficiency, and potential in synthetic chemistry and biologically meaningful natural product modification.
- Liu, Hong-Xin,Dang, Ya-Qian,Yuan, Yun-Fei,Xu, Zhi-Fang,Qiu, Sheng-Xiang,Tan, Hai-Bo
-
supporting information
p. 5584 - 5587
(2016/11/17)
-
- Regioselective benzoylation of diols and carbohydrates by catalytic amounts of organobase
-
A novel metal-free organobase-catalyzed regioselective benzoylation of diols and carbohydrates has been developed. Treatment of diol and carbohydrate substrates with 1.1 equiv. of 1-benzoylimidazole and 0.2 equiv. of 1,8-diazabicyclo[5.4.0]undec-7-ene (DB
- Lu, Yuchao,Hou, Chenxi,Ren, Jingli,Xin, Xiaoting,Xu, Hengfu,Pei, Yuxin,Dong, Hai,Pei, Zhichao
-
-
- A green and convenient method for regioselective mono and multiple benzoylation of diols and polyols
-
An efficient method for regioselective benzoylation of diols and polyols was developed. The benzoylation is catalyzed by only 0.2 equiv of benzoate anion in acetonitrile with the addition of a stoichiometric amount of benzoic anhydride under very mild condition, leading to high yields. Compared with all other methods, this method shows particular advantage in regioselective multiple benzoylation of polyols, and in avoiding the use of any metal-based catalysts and any amine bases, which is more environment-friendly.
- Zhang, Xiaoling,Ren, Bo,Ge, Jiantao,Pei, Zhichao,Dong, Hai
-
p. 1005 - 1010
(2016/02/03)
-
- A microwave-assisted highly practical chemoselective esterification and amidation of carboxylic acids
-
The ubiquitousness of esters and amide functionalities makes their coupling reaction one of the most sought-after organic transformations. Herein, we have described an efficient microwave-assisted synthesis of esters and amides. Soluble triphenylphosphine, in conjugation with molecular iodine, gave the desired products without the requirement for a base/catalyst. In addition, a solid-phase synthetic route is incorporated for the said conversion, which has added advantages over solution-phase pathways, such as low moisture sensitivity, easy handling, isolation of the product by simple filtration, and reusability. In short, our method is simple, mild, green, and highly chemoselective in nature.
- Pathak, Gunindra,Das, Diparjun,Rokhum, Lalthazuala
-
p. 93729 - 93740
(2016/10/21)
-
- Simple and practical method for selective acylation of primary hydroxy group catalyzed by N-methyl-2-phenylimidazole (Ph-NMI) or 2-phenylimidazo[2,1-b]benzothiazoles (Ph-IBT)
-
N-Methyl-2-phenylimidazole (Ph-NMI) and 2-phenylimidazo[2,1-b]benzothiazoles (Ph-IBT) catalyzed selective acylation of primary alcohols using acid anhydrides. The Ph-NMI- or Ph-IBT-catalyzed reaction using (PhCO)2O as an acylating agent could particularly acylate the primary hydroxy group of 1,n-diols (n ≥ 3) with a high, synthetically useful selectivity.
- Ibe, Kouta,Hasegawa, Yu-Suke,Shibuno, Misuzu,Shishido, Tsukasa,Sakai, Yuzo,Kosaki, Yu,Susa, Keisuke,Okamoto, Sentaro
-
p. 7039 - 7042
(2015/01/08)
-
- Stereoselective synthesis of ophiocerin B
-
A stereoselective total synthesis of ophiocerin B is reported by asymmetric synthesis, starting from L-malic acid. Of the three stereogenic centers, the vic-diols C-3, C-4 were obtained by Sharpless asymmetric dihydroxylation. ARKAT-USA, Inc.
- Akkala, Bhasker,Damera, Krishna
-
p. 164 - 170
(2013/09/12)
-
- Regioselective, borinic acid-catalyzed monoacylation, sulfonylation and alkylation of diols and carbohydrates: Expansion of substrate scope and mechanistic studies
-
Synthetic and mechanistic aspects of the diarylborinic acid-catalyzed regioselective monofunctionalization of 1,2- and 1,3-diols are presented. Diarylborinic acid catalysis is shown to be an efficient and general method for monotosylation of pyranoside derivatives bearing three secondary hydroxyl groups (7 examples, 88% average yield). In addition, the scope of the selective acylation, sulfonylation, and alkylation is extended to 1,2- and 1,3-diols not derived from carbohydrates (28 examples); the efficiency, generality, and operational simplicity of this method are competitive with those of state-of-the-art protocols including the broadly applied organotin-catalyzed or -mediated reactions. Mechanistic details of the organoboron-catalyzed processes are explored using competition experiments, kinetics, and catalyst structure-activity relationships. These experiments are consistent with a mechanism in which a tetracoordinate borinate complex reacts with the electrophilic species in the turnover-limiting step of the catalytic cycle.
- Lee, Doris,Williamson, Caitlin L.,Chan, Lina,Taylor, Mark S.
-
supporting information; experimental part
p. 8260 - 8267
(2012/07/14)
-
- Total synthesis of macrosphelide M from diacetone glucose
-
The total synthesis of macrosphelide M is described. The key steps include the preparation of the acid and alcohol fragments from diacetone glucose and (S)-malic acid, respectively, followed by Yamaguchi esterification and macrocyclization of the tris-olefin by ring-closing metathesis. Finally, one-pot deprotection of the PMB and TBS groups with TiCl4 results in the target. The C-3/C-4 stereocenters of diacetone glucose are used for the introduction of four stereocenters, whereas the fifth stereocenter is realized from (S)-malic acid. The total synthesis of macrosphelide M was achieved from diacetone glucose and (S)-malic acid. The key steps include Yamaguchi esterification and macrocyclization of the tris-olefin by the second-generation Grubbs catalyst.
- Sharma, Gangavaram V. M.,Reddy, Post Sai
-
experimental part
p. 2414 - 2421
(2012/05/20)
-
- Selective esterifications of primary alcohols in a water-containing solvent
-
Oxyma and an oxyma derivative, (2,2-dimethyl-1,3-dioxolan-4-yl)methyl 2-cyano-2-(hydroxyimino)acetate (5b), displayed a remarkable effect on selective esterifications of primary alcohols. A wide range of carboxylic acids could be esterified with primary alcohols by using EDCI, NaHCO3, and Oxyma or Oxyma derivative 5b in 5% H2O-CH3CN. Oxyma derivative 5b is particularly useful, since it could be removed after the reaction via a simple basic or an acidic aqueous workup procedure.
- Wang, Yong,Aleiwi, Bilal A.,Wang, Qinghui,Kurosu, Michio
-
supporting information
p. 4910 - 4913,4
(2012/12/12)
-
- Selective esterifications of primary alcohols in a water-containing solvent
-
Oxyma and an oxyma derivative, (2,2-dimethyl-1,3-dioxolan-4-yl)methyl 2-cyano-2-(hydroxyimino)acetate (5b), displayed a remarkable effect on selective esterifications of primary alcohols. A wide range of carboxylic acids could be esterified with primary alcohols by using EDCI, NaHCO3, and Oxyma or Oxyma derivative 5b in 5% H2O-CH3CN. Oxyma derivative 5b is particularly useful, since it could be removed after the reaction via a simple basic or an acidic aqueous workup procedure.
- Wang, Yong,Aleiwi, Bilal A.,Wang, Qinghui,Kurosu, Michio
-
supporting information
p. 4910 - 4913
(2013/01/15)
-
- Efficient and controllably selective preparation of esters using uronium-based coupling agents
-
Carboxylic acid esters can be prepared in excellent yields at room temperature from an acid and either a phenol or an aliphatic alcohol using the peptide coupling reagents, TBTU, TATU, or COMU, in the presence of organic bases. Reactions using TBTU and TATU are faster but do not occur with tertiary alcohols. Selectivity between reaction with primary or secondary alcohols in diols and polyols can be achieved with choice of base and coupling agent.
- Twibanire, Jean-D'Amour K.,Grindley, T. Bruce
-
supporting information; experimental part
p. 2988 - 2991
(2011/08/04)
-
- Selective mono-acylation of 1,2- and 1,3-diols using (α,α- difluoroalkyl)amines
-
In the reaction of N,N-diethyl-α,α-difluorobenzylamine (DFBA) with 1,2- or 1,3-diols, selective mono-benzoylation occurs to afford mono-esters of the diols in good yield. The reaction is completed under mild conditions in a short reaction time. Further, prim-, sec-, and tert-diols and catechol can be converted to the corresponding mono-benzoates. DFBA is used for the protection of the hydroxy group in sugars. The selective mono-nicotinylation, formylation and pivaloylation of diols are also performed by using the corresponding difluoroalkylamines.
- Wakita, Natsumi,Hara, Shoji
-
experimental part
p. 7939 - 7945
(2010/10/19)
-
- Oxidative transformation of 1,3-dioxacycloalkanes induced by chlorine dioxide
-
The products and kinetic regularities of the reactions of 1,3-dioxacycloalkanes with chlorine dioxide were studied. The effects of the nature of solvent and the temperature on the reaction rate were considered and the activation parameters were determined.
- Abdrakhmanova,Kabal'nova,Rol'nik,Yagafarova,Shereshovets
-
p. 1755 - 1760
(2007/10/03)
-
- Transformations of cyclic acetals under the action of some organic and inorganic oxidants
-
Liquid-phase oxidation of cyclic acetals and 2,2-disubstituted 1,3-dioxacyclanes with dimethyldioxirane, Caro salt, potassium persulfate, and complex of potassium chlorodiperoxochromate with 15-crown-5 was studied.
- Akbalina,Zlotskii,Kabal'nova,Grigor'ev,Kotlyar,Shereshovets
-
p. 1120 - 1122
(2007/10/03)
-
- Facile oxidative cleavage of benzylidene acetals using molecular oxygen catalyzed by N-hydroxyphthalimide/Co(OAc)2
-
Benzylidene acetals derived from 1,2- and 1,3-diols undergo facile oxidative cleavage to give hydroxy benzoate esters with molecular oxygen in the presence of catalytic amount of N-hydroxyphthalimide/Co(OAc)2.
- Chen, Yongsheng,Wang, Peng George
-
p. 4955 - 4958
(2007/10/03)
-
- Asymmetric addition of an electrophile to naphthalenes promoted and stereodirected by alcohol
-
4-Phenyl-1,2,4-triazoline-3,5-dione (PTAD) reacts with 1-methoxy-4-methylnaphthalene to give the 1,4-addition product in the presence of methanol; the reaction does not proceed in the absence of the alcohol. Methoxy exchange (with CD3OD) was al
- Fujita,Matsushima,Sugimura,Tai,Okuyama
-
p. 2946 - 2957
(2007/10/03)
-
- A convenient and practical method for the selective benzoylation of primary hydroxyl groups using microwave heating
-
A convenient method for the selective protection of primary hydroxyl groups in 1,n diols is described. The use of microwave heating is shown to be advantageous.
- Caddick, Stephen,McCarroll, Andrew J,Sandham, David A
-
p. 6305 - 6310
(2007/10/03)
-
- Chemo- and stereoselective monobenzoylation of 1,2-diols catalyzed by organotin compounds
-
A new facile method for monoacylation of diols has been developed. A variety of cyclic and acyclic diols, in particular 1,2-diols, were selectively monobenzoylated in good yields by the reaction with benzoyl chloride in the presence of a catalytic amount of dimethyltin dichloride and inorganic bases such as potassium carbonate. Furthermore, the method was successfully applied to a kinetic resolution of racemic 1-phenyl-1,2- ethanediol using a chiral organotin catalyst. The ee was dependent on the kind of base, water as an additive, and the reaction temperature.
- Iwasaki, Fumiaki,Maki, Toshihide,Onomura, Osamu,Nakashima, Waka,Matsumura, Yoshihiro
-
p. 996 - 1002
(2007/10/03)
-
- 2-Phenyl(heteryl)-Substituted 1,3-Dioxanium Salts in the Reaction with Trimethylsilylethynylmagnesium Bromide
-
A method for preparation of 2-α-furyl(α-thienyl)-4-methyl-1,3-dioxanium hexachloroantimonates, their hydrolysis and reaction with trimethylsilylethynylmagnesium bromide are described.
- Kosulina, T. P.,Ol'khovskaya, L. I.,Kul'nevich, V. G.,Karataeva, F. Kh.
-
p. 1538 - 1541
(2007/10/03)
-
- Use of the Mitsunobu reaction in the synthesis of polyamines
-
The Mitsunobu reaction has been used in the synthesis of polyamine analogues. The synthesis of the (R,R), (S,S) and meso-isomers of a tetraamine are described. The chemistry was used to synthesize a fluorinated polyamine analog and a hexaamine.
- Edwards, Michael L.,Stemerick, David M.,McCarthy, James R.
-
p. 5579 - 5590
(2007/10/02)
-
- Organotin-Mediated Monoacylation of Diols with Reversed Chemoselectivity: A Convenient Synthetic Method
-
The organotin-mediated monoesterification of unsymmetrical diols with reversed chemoselectivity has been explored to ascertain scope and limits of the method and to provide an easy and convenient synthetic procedure.The reaction has been performed on a set of substituted diols with some acylating agents usually employed as protecting groups.Two different procedures have been devised to obtain either the desired diol monoesters directly or the corresponding trialkylsilyl ethers as protected derivatives.The latter provides a convenient approach to the preparation of easily interconvertible diol monoesters.Also, the reaction has been optimized as a one-pot procedure, avoiding the isolation and purification of the stannylated intermediates.The reversed monoesterification method has been successfully applied to 1,2-, 1,3-, and 1,4-diols of primary-secondary, primary-tertiary, and secondary-tertiary types and to ether functions containing 1,2-diols.Within its limits, the described method represents the first direct one-pot monoesterification of diols at the most substituted site, allowing some remarkable achievements as (a) an almost regiospecific reversed monobenzoylation of some 1,2-diols, (b) the selective acylation of the tertiary hydroxyl of a primary-tertiary diol, and (c) a highly selective preparation of secondary pivalate of primary-secondary diols.
- Reginato, Gianna,Ricci, Alfredo,Roelens, Stefano,Scapecchi, Serena
-
p. 5132 - 5139
(2007/10/02)
-
- Palladium(II)-catalysed Oxidative Ring Cleavage of Cyclic Acetals with t-Butyl Hydroperoxide: Preparation of Monoesters of Diols
-
Reaction of five- and six-membered cyclic acetals with tBuOOH in the presence of palladium(II) catalyst gives monoesters of diols in good yields.
- Hosokawa, Takahiro,Imada, Yasushi,Murahashi, Shun-Ichi
-
p. 1245 - 1246
(2007/10/02)
-
- SYNTHESIS OF 1,3-DIOXANIUM HEXACHLOROANTIMONATES
-
2-Alkyl(aryl, 2-furyl, and β-vinylphenyl)-1,3-dioxanium hexachloroantimonates were obtained by acylation of 1,3-dioxanes with carboxylic acid chlorides in the presence of antimony pentachloride.
- Kosulina, T. P.,Gromachevskaya, E. V.,Falina, L. A.,Kolesnikov, A. G.,Kul'nevich, V. G.
-
p. 374 - 376
(2007/10/02)
-
- Enantiomerically Pure Synthetic Building Blocks with Four C-Atoms and Two or Three Functional Groups from β-Hydroxy-butanoic, Malic, and Tartaric Acid
-
The pool of chiral, non-racemic electrophilic building blocks, which are available from simple natural products in both enantiomeric forms is enlarged by the epoxides 3, 5, and 10, by the tosylate 12a, and by the aldehydes 18 (cf. symbols A-D, 14, and Scheme 1).Key steps of the conversions leading from hydroxyacids to the building blocks are: epoxide-opening by triethylborohydride (1 --> 2a) and tosylate reduction (12a --> 12b); the Mitsunobu inversion (2a --> 4a); the reduction of (R,R)-tartaric ester to (R)-malic ester by NBS (N-bromosuccinimide) opening of the benzaldehyde acetal 8 and tin hydride reduction (6c -->7c); the enantiomer enrichment of optically active ethyl β-hydroxy-butanoate through the crystalline dinitrobenzoate 21b.Detailed procedures are given for large scale preparations of the key intermediates.The enantiomeric purities of the building blocks are secured by correlations.
- Hungerbuehler, Ernst von,Seebach, Dieter,Wasmuth, Daniel
-
p. 1467 - 1487
(2007/10/02)
-
- DIALKYL ACYLPHOSPHONATES: A NEW ACYLATING AGENT OF ALCOHOLS
-
Diethyl benzoylphosphonate (1) underwent facile benzoylation of alcohols in the presence of DBU.Reactions of diols containing primary and secondary hydroxyl groups with 1 gave predominantly monobenzoates in which primary hydroxyl groups were highly selectively benzoylated.Related acylations were also described.
- Sekine, Mitsuo,Kume, Akiko,Hata, Tsujiaki
-
p. 3617 - 3620
(2007/10/02)
-