- Asymmetric desymmetrization of meso-1,2-diols by phosphinite derivatives of cinchona alkaloids
-
An effective catalyst for the asymmetric monobenzoylation of meso-1, 2-diols was designed - the phosphinite derivative of cinchonine (see formula). In the presence of 30 mol % of this catalyst the monobenzoylated products were obtained with high yields an
- Mizuta, Shinya,Sadamori, Mikito,Fujimoto, Tetsuya,Yamamoto, Iwao
-
-
Read Online
- Highly efficient catalytic asymmetric acylation of meso-1,2-diols with benzoyl chloride in the presence of a chiral diamine combined with Et3N
-
Catalytic asymmetric acylation of meso-1,2-diols has been successfully performed by the reaction with benzoyl chloride in the presence of 0.5 mol% of chiral diamine derived from (S)-proline combined with a stoichiometric amount of triethylamine to give th
- Oriyama, Takeshi,Imai, Keisuke,Sano, Tomohumi,Hosoya, Takeshi
-
-
Read Online
- Diamine ligands for asymmetric catalysis: Facile synthesis of C 2-symmetric piperazines from Seebach's oxazolidinone
-
C2-Symmetrical hemiaminal ethers and diamines with a piperazine core were synthesized starting from Seebach's oxazolidinone. The new methodology is based on the dimerization of α-amino aldehydes to bicyclic bishemiaminal ethers, followed by red
- Ka?uza, Zbigniew,C?wiek, Rafa?,Dygas, Miros?aw,Kalicki, Przemys?aw
-
-
Read Online
- Desymmetrization of meso diols using enantiopure zinc (II) dimers: Synthesis and chiroptical properties
-
The one-pot metal templated synthesis of enantiopure binuclear Zn (II) complexes Zn2L1–Zn2L4 were obtained by treating (1R,2R)-diphenylethylenediamine or (1S,2S)-diphenylethylenediamine with 2-hydroxy-5-methyl-1
- Chinnaraja, Eswaran,Arunachalam, Rajendran,Samanta, Jayanta,Natarajan, Ramalingam,Subramanian, Palani S.
-
-
- Binuclear Double-Stranded Helicates and Their Catalytic Applications in Desymmetrization of Mesodiols
-
The ligand L1 of 4-methyl-2,6-diformylphenol and L2 of 4-tert-butyl-2,6-diformylphenol are synthesized through Schiff base condensation with rac-, (R)-(+), or (S)-(-)-1,1′-binaphthyl-2,2′-diamine (BNDA). As a result, the racemic L1rac, L2rac, and enantiopure L1RR, L1SS, L2RR, and L2SS ligands are obtained incorporating Cu(II) and Zn(II) salts by a simple one-pot metal template method. The series of dinuclear complexes of [M2LX2] (here, M = Cu2+, Zn2+ X = acetate ion, chloride ion; L = L1RR, L1SS, L1rac, L2RR, L2SS, L2rac) formulas are obtained in common. Among them, the single crystal X-ray structures for [Zn2L1rac(OAc)2] and [Zn2L1SSCl2] complexes are obtained. The detailed crystal structure and the chiroptical studies performed on these complexes dictates a self-sorting behavior in their self-assembly process and illustrate a chirality transfer from the ligand to the metal center on the complexes. The enantiopure dinuclear complexes [M2LRRX2] and [M2LSSX2] generate enantiopure λλ and ΔΔ isomers, respectively, but the racemic complexes produce only homochiral λλ and ΔΔ assemblies. The detailed studies based on UFLC (Ultra Fast Liquid Chromatography), CD, and single crystal X-ray structure together show the absence of heterochiral λΔ mesocate. All these complexes are adapted as catalysts for desymmetrization of various mesodiols, and the enantiopure complexes are found to give efficient enantioselectivity in desymmetrization of mesodiols with benzoyl chloride to monobenzoylated ester providing 98% yield and 92% ee.
- Chinnaraja, Eswaran,Arunachalam, Rajendran,Suresh, Eringathodi,Sen, Shovan K.,Natarajan, Ramalingam,Subramanian, Palani S.
-
p. 4465 - 4479
(2019/03/26)
-
- Selective Monoacylation of Diols and Asymmetric Desymmetrization of Dialkyl meso-Tartrates Using 2-Pyridyl Esters as Acylating Agents and Metal Carboxylates as Catalysts
-
With 2-pyridyl benzoates as acylating agents and Zn(OAc)2 as a catalyst, 1,2-diols, 1,3-diols, and catechol were selectively monoacylated. Furthermore, the highly enantioselective desymmetrization of meso-tartrates was achieved for the first time, utilizing 2-pyridyl esters and NiBr2/AgOPiv/Ph-BOX in CH3CN or CuCl2/AgOPiv/Ph-BOX in EtOAc catalyst systems (up to 96% ee). The latter catalyst system was also effective for the kinetic resolution of dibenzyl dl-tartrate.
- Hashimoto, Yuki,Michimuko, Chiaki,Yamaguchi, Koki,Nakajima, Makoto,Sugiura, Masaharu
-
p. 9313 - 9321
(2019/08/12)
-
- Use of copper(II)/diamine catalysts in the desymmetrisation of?meso-diols and asymmetric Henry reactions: comparison of?(?)-sparteine and (+)-sparteine surrogates
-
Four new copper(II)/diamine complexes comprising some (+)-sparteine surrogates and a cyclohexane-derived diamine were prepared and evaluated as chiral catalysts in desymmetrisation of meso-diols and asymmetric Henry reactions. Mono-benzoylation reactions generated two products with high enantioselectivity (90:10 to 97:3 er). Asymmetric Henry reactions gave nitro alcohols in 90:10 to 98:2 er. Notably, the sense of induction with the (+)-sparteine surrogates was opposite to that obtained using the copper(II)/(?)-sparteine complex. One of the nitro alcohol products was utilised in a concise synthesis of a chiral morpholine.
- Canipa, Steven J.,Stute, Annika,O'Brien, Peter
-
p. 7395 - 7403
(2017/09/12)
-
- Kinetic resolution of secondary alcohols by chiral dmap derivatives prepared by the Ugi multicomponent reaction
-
The kinetic resolution of secondary alcohols was examined by new chiral DMAP derivatives, which can readily be prepared by the Ugi multicomponent reaction in a one-pot operation. The initial screening of DMAP derivatives indicated that the catalyst bearing L-valine with an S configuration at the a-position of amide showed the best stereoselectivity factor. After the reaction conditions were optimized with (S,S)-4a in the kinetic resolution of secondary alcohols, various acyclic and cyclic secondary alcohols could be resolved with an s -factor of up to 12.
- Mandai, Hiroki,Irie, Shunsuke,Akehi, Masaru,Yuri, Kazunobu,Yoden, Masaaki,Mitsudo, Koichi,Suga, Seiji
-
p. 329 - 340
(2013/03/28)
-
- C2-Symmetric hemiaminal ethers and diamines: New ligands for copper-catalyzed desymmetrization of meso-1,2-diols and asymmetric Henry reactions
-
The synthesis of novel, enantiomerically pure C2-symmetrical hemiaminal ethers and diamines containing piperazine core is presented. The key steps of the synthesis involve the dimerization of an in situ generated α-amino aldehyde into the corresponding cyclic bis-hemiaminal, followed by dehydration in the presence of a base to give a 7-oxa-2,5-diaza-bicyclo[2.2.1] heptane derivative, which can be regarded as a bicyclic bis-hemiaminal inner ether. These compounds represent a new class of molecule, with a structure unambiguously established for the first time. Finally, sodium triacetoxy-borohydride reduction gave the corresponding diamines. Both classes of compounds, new diamines and hemiaminal ethers, were shown to be good ligands for the copper(II)-catalyzed desymmetrization of meso-diols (up to 87% ee) and Henry reactions (up to 84% ee).
- Kaluza, Zbigniew,Bielawski, Krzysztof,Cwiek, Rafal,Niedziejko, Piotr,Kaliski, Przemyslaw
-
p. 1435 - 1442
(2013/12/04)
-
- Kinetic resolution of secondary alcohols by the combination of a chiral Br?nsted acid, DABCO, and acetyl chloride
-
An efficient and simple protocol for the kinetic resolution of secondary alcohols is presented. The new system is based on a combination of chiral Br?nsted acid, DABCO, and acetyl chloride and gives various enantioenriched alcohols with selectivity factors up to 105.
- Mandai, Hiroki,Murota, Kyouta,Mitsudo, Koichi,Suga, Seiji
-
supporting information; experimental part
p. 3486 - 3489
(2012/08/14)
-
- Oxidative esterification, thioesterification, and amidation of aldehydes by a two-component organocatalyst system using a chiral N-heterocyclic carbene and redox-active riboflavin
-
Flavin of the month! Triazolium-derived N-heterocyclic carbenes (NHCs) and a flavin catalyzed the oxidative esterification, thioesterification, and amidation of aldehydes with various alcohols, thiols, and amines, respectively, with O2 as the terminal oxidant (see scheme; R1=aryl; R2, R3=alkyl or aryl). By using a chiral NHC catalyst, the enantioselective acylation promoted the kinetic resolution of racemic alcohols and the desymmetrization of a meso-diol.
- Iwahana, Soichiro,Iida, Hiroki,Yashima, Eiji
-
supporting information; experimental part
p. 8009 - 8013
(2011/08/22)
-
- Truncated Cinchona alkaloids as catalysts in enantioselective monobenzoylation of meso-1,2-diols
-
Readily synthesised quincorine and quincoridine derived chiral diamines efficiently catalyse the asymmetric monobenzoylation of cyclic and acyclic meso-1,2-diols. The Royal Society of Chemistry.
- Kuendig, E. Peter,Enriquez Garcia, Alvaro,Lomberget, Thierry,Perez Garcia, Pablo,Romanens, Patrick
-
supporting information; body text
p. 3519 - 3521
(2009/02/05)
-
- Design and synthesis of novel C2-symmetric chiral piperazines and an application to asymmetric acylation of σ-symmetric 1,2-diols
-
(Chemical Equation Presented) A novel alicyclic chiral C 2-symmetric piperazine, (S,S)-7, is designed and synthesized from L-proline. Benzoylation of a series of cyclic and acyclic meso-1,2-diols with a catalytic amount of (S,S)-7 and CuCl2 provided optically active monobenzoates with high enantioselectivity.
- Nakamura, Daisuke,Kakiuchi, Kiyomi,Koga, Kenji,Shirai, Ryuichi
-
p. 6139 - 6142
(2007/10/03)
-
- Asymmetric acyl-transfer promoted by readily assembled chiral 4-N,N-dialkylaminopyridine derivatives
-
The development of a new class of chiral 4-N,N-dialkylaminopyridine acyl-transfer catalysts capable of exploiting both van der Waals (π) and H-bonding interactions to allow remote chiral information to stereochemically control the kinetic resolution of sec-alcohols with moderate to excellent selectivity (s = 6-30). Catalysts derived from (S)-α,α- diarylprolinol are considerably superior to analogues devoid of a tertiary hydroxyl moiety and possess high activity and selectivity across a broad range of substrates. The Royal Society of Chemistry 2006.
- Dalaigh, Ciaran O.,Hynes, Stephen J.,O'Brien, John E.,McCabe, Thomas,Maher, Declan J.,Watson, Graeme W.,Connon, Stephen J.
-
p. 2785 - 2793
(2008/03/14)
-
- Chiral boron-bridged bisoxazolines: Readily available anionic ligands for asymmetric catalysis
-
Asymmetric cyclopropanation and monobenzoylation reactions of mesa diols employing borabox catalysts 1 (M = Cu) result in high enantioselectivities. The borabox ligands are anionic analogues of the bisoxazolines 2 and are readily prepared by lithiation of
- Mazet, Clement,Koehler, Valentin,Pfaltz, Andreas
-
p. 4888 - 4891
(2007/10/03)
-
- Kinetic resolution of sec-alcohols using a new class of readily assembled (S)-proline-derived 4-(pyrrolidino)-pyridine analogues
-
We report the development of a new class of readily prepared chiral 4-(pyrrolidino)-pyridine catalysts capable of exploiting both van der Waals (π) and H-bonding interactions, thus allowing remote chiral information to stereo-chemically control the kinetic resolution of sec-alcohols. The Royal Society of Chemistry 2005.
- Dalaigh, Ciaran O.,Hynes, Stephen J.,Maher, Declan J.,Connon, Stephen J.
-
p. 981 - 984
(2007/10/03)
-
- A new convenient method for selective monobenzoylation of diols
-
A new facile method for monoacylation of diols has been developed. A variety of cyclic and acyclic diols, in particular 1,2-diols, was selectively monobenzoylated in good yields by their reaction with benzoyl chloride in the presence of a catalytic amount of dimethyltin dichloride and inorganic bases.
- Maki, Toshihide,Iwasaki, Fumiaki,Matsumura, Yoshihiro
-
p. 5601 - 5604
(2007/10/03)
-
- Asymmetric acylation of meso-diols with benzoyl halide in the presence of a chiral diamine
-
Nonenzymatic desymmetrization of cis-1,2-cyclohexanediol by the asymmetric acylation with achiral benzoyl chloride in the presence of a chiral diamine derived from (S)-proline took place to give monobenzoate in high optical yield.
- Oriyama, Takeshi,Imai, Keisuke,Hosoya, Takeshi,Sano, Tomohumi
-
p. 397 - 400
(2007/10/03)
-