105367-39-3

Upstream product

• 100-42-5 styrene 
• 65437-23-2 d-menthyl diazoacetate 
• 63254-50-2 L-menthyl diazoacetate 

Relevant academic research and scientific papers

Preparation and application of bisoxazoline ligands with a chiral spirobiindane skeleton for asymmetric cyclopropanation and allylic oxidation

A new type of bisoxazoline ligand 4 (abbreviated as SpiroBOX) containing a chiral spirobiindane scaffold were easily prepared in high yields from enantiomerically pure 1,1′-spirobiindane-7,7′-diol (SPINOL) with 1,1′-spirobiindane-7,7′-dicarboxylic acid as

Bisoxazoline ligands with an axial-unfixed biaryl backbone: the effects of the biaryl backbone and the substituent at oxazoline ring on Cu-catalyzed asymmetric cyclopropanation

The synthesis of novel C2-symmetric bisoxazoline ligands with an axial-unfixed biaryl backbone and different substituents at the oxazoline ring is reported. The diastereomer equilibrium of these ligands in solution and their complexation behavi

In search of high stereocontrol for the construction of cis-disubstituted cyclopropane compounds. Total synthesis of a cyclopropane-configured urea-PETT analogue that is a HIV-1 reverse transcriptase inhibitor.

[reaction: see text] A new azetidine-ligated dirhodium(II) catalyst that possesses a l-menthyl ester attachment provides significant diastereocontrol and high enantiocontrol for the formation of cis-cyclopropane products from reactions of substituted styr

Asymmetric cyclopropanation in protic media conducted by chiral bis(hydroxymethyl-dihydrooxazolyl)pyridine-ruthenium catalysts

Cyclopropanation of styrene with diazoacetates, performed in aqueous/organic biphasic media or homogeneous alcoholic media in the combination of toluene by using chiral bis(hydroxymethyldihydrooxazolyl)pyridine-ruthenium catalyst, resulted in high enantio

Asymmetric inter- and intramolecular cyclopropanation of alkenes catalyzed by chiral ruthenium porphyrins. Synthesis and crystal structure of a chiral metalloporphyrin carbene complex

Extensive investigations of asymmetric intermolecular cyclopropanation of terminal alkenes with diazoacetates catalyzed by ruthenium porphyrin [Ru(P*)(CO)(EtOH)] (1, H2P* = 5,10,15,20-tetrakis-{(1S,4R,5R,8S)-1,2,3,4,5,6,7,8-octahydro-1,4:5,8- dimethanoanthracene-9-yl}porphyrin) and the application of catalyst 1 to asymmetric intramolecular cyclopropanation of allylic or homoallylic diazoacetates are described. The intermolecular cyclopropanation of styrene and its derivatives with ethyl diazoacetate afforded the corresponding cyclopropyl esters in up to 98% ee with high trans/cis ratios of up to 36 and extremely high catalyst turnovers of up to 1.1 × 104. Examination of the effects of temperature, diazoacetate, solvent, and substituent in the intermolecular cyclopropanation reveals that (i) both enantioselectivity and trans selectivity increase with decreasing temperature, (ii) sterically encumbered diazoacetates N2CHCO2R such as R = But, and donor solvents, such as diethyl ether and tetrahydrofuran, are beneficial to the trans selectivity, and (iii) electron-donating para substituents on styrene accelerate the cyclopropanations, with the log(kx/kH) vs σ+ plot for para-substituted styrenes p-X-C6H4CH=CH2 (X = MeO, Me, Cl, CF3) exhibiting good linearity with a small negative ρ+ value of -0.44 ± 0.09. In the case of intramolecular cyclopropanation, complex 1 promoted the decomposition of a series of allylic diazoacetates to form the cyclopropyl lactones in up to 85% ee, contributing the first efficient metalloporphyrin catalyst for an asymmetric intramolecular cyclopropanation. Both the inter- and intramolecular cyclopropanations were proposed to proceed via a reactive chiral ruthenium carbene intermediate. The enantioselectivities in these processes were rationalized on the basis of the X-ray crystal structures of closely related stable chiral carbene complexes [Ru(P*)(CPh2)] (2) and [Ru(P*)(C(Ph)-CO2CH2CH=CH2)] (3) obtained from reactions of complex 1 with N2CPh2 and N2C(Ph)CO2CH2CH=CH2, respectively.

Novel chiral bisoxazoline ligands with a biphenyl backbone: Preparation, complexation, and application in asymmetric catalytic reactions

Novel C2-symmetric chiral bisoxazoline ligands 1 were easily prepared from enantiomerically pure 2-amino alcohols and achiral 2,2′-biphenyldicarboxylic acid via the corresponding amide and mesylate as intermediates. Since these ligands bear only two ortho-substituents on the biphenyl backbone, the biphenyl axis is not fixed, and the two diastereomers of these ligands exist in equilibrium in solution. Interestingly, when the ligands 1 were coordinated with a metal ion, only one of the two possible diastereomer complexes, an (S,aS,S)-complex, can be formed depending on the combination of the ligand and the metal ion. Thus, copper(I) afforded only the (S,a,S,S)-complexes with all ligands 1, while zinc(II), palladium(II), and silver(I) afforded the (S,aS,S)-complexes as the sole product only with 1b, which has a bulky terf-butyl group on the oxazoline ring, and a mixture of the two diastereomer complexes with 1a,c,d. The copper(I)-catalyzed asymmetric cyclopropanation of styrene with diazoacetate proceeded successfully with these ligands and good to excellent enantioselectivities were afforded.

First enantioselective catalyst based on a chiral terpyridine: Synthesis of new C2-symmetric 2,2':6',2''-terpyridine ligands and copper-catalyzed enantioselective cyclopropanation of alkenes

New C2-symmetric chiral 2,2':6',2''-terpyridines were prepared from readily available homochiral materials. Copper complexes of these ligands were prepared in situ and their catalytic activities in cyclopropanations of alkenes with alkyl diazoacetate to give cyclopropyl esters were studied. In all cases, the cyclopropyl ester yields were excellent and enantioselectivities up to 94% ee were observed. Competition experiments revealed that electron-donating substituents on styrene accelerate the reaction. Hammett plot exhibited a good linearity with negative ρ+ value (-0.79). Copyright (C) 2000 Elsevier Science Ltd.

Asymmetric cyclopropanation of olefins with diazoacetate using chiral copper catalysts

Chiral 2-(2-aryl- or 2-alkyl-sufonylamino)phenyl-4-phenyl-1,3-oxazolines were found to be effective ligands for copper-catalyzed enantioselective cyclopropanation reaction of olefins. The reaction of styrene with d-menthyl diazoacetate in the presence of optically active copper catalysts gave cyclopropanation products in a ratio of trans: cis = 83: 17 with 63% ee (trans) and 84% ee (cis).

Highly Enantioselective Intermolecular Cyclopropanation Catalyzed by Dirhodium(II) Tetrakis[3(S)-phthalimido-2-piperidinonate]: Solvent Dependency of the Enantioselection

The enantioselectivity in cyclopropanations catalyzed by dirhodium(II) tetrakis[3(S)-phthalimido-2-piperidinonate] has been found to be substantially improved by employing ether as the rarely used solvent. Cyclopropanations of styrenes or 1,1-disubstituted alkenes with 2,4-dimethyl-3-pentyl diazoacetate in ether are promoted by this catalyst to afford the corresponding cyclopropane products in the highest levels of enantioselectivity (up to 98% ee) reported to date for the dirhodium(II)-catalyzed intermolecular cyclopropanation reactions.

Dirhodium(II)tetrakis[3(S)-phthalimido-2-piperidinonate]: A novel dirhodium(II) carboxamidate catalyst for asymmetric cyclopropanation

Dirhodium(II) tetrakis[3(S)-phthalimido-2-piperidinonate] catalyzes cyclopropanation of α-methylstyrene with d-menthyl diazoacetate to give d-menthyl (1S,2S)-2-methyl-2-phenylcyclopropanecarboxylate of 90% de.