81699-66-3Relevant articles and documents
Highly diastereoselective and enantioselective olefin cyclopropanation using engineered myoglobin-based catalysts
Bordeaux, Melanie,Tyagi, Vikas,Fasan, Rudi
supporting information, p. 1744 - 1748 (2015/02/19)
Using rational design, an engineered myoglobinbased catalyst capable of catalyzing the cyclopropanation of aryl-substituted olefins with catalytic proficiency (up to 46800 turnovers) and excellent diastereo- and enantioselectivity (98-99.9%) was developed. This transformation could be carried out in the presence of up to 20 gL-1 olefin substrate with no loss in diastereo- and/or enantioselectivity. Mutagenesis and mechanistic studies support a cyclopropanation mechanism mediated by an electrophilic, heme-bound carbene species and a model is provided to rationalize the stereopreference of the protein catalyst. This work shows that myoglobin constitutes a promising and robust scaffold for the development of biocatalysts with carbene-transfer reactivity.
Catalytic and asymmetric cyclopropanation of alkenes catalysed by rhenium(I) bipyridine and terpyridine tricarbonyl complexes
Yeung, Chi-Tung,Teng, Pang-Fei,Yeung, Ho-Lun,Wong, Wing-Tak,Kwong, Hoi-Lun
, p. 3859 - 3864 (2008/10/09)
Re(i) tricarbonyl bipyridine and terpyridine complexes catalyse stereospecific cyclopropanation of alkenes; high selectivity of cyclopropane vs coupling and an ee of 73% and 62% for cis- and trans-cyclopropanes of styrene respectively were achieved with the [Re(L)(CO)3(MeCN)]OTf complex (L = chiral C2-symmetric terpyridine ligand). The Royal Society of Chemistry 2007.
Chiral C2-symmetric bisferrocenyldiamines as ligands for transition metal catalyzed asymmetric cyclopropanation and aziridination
Cho, Dong-Jei,Jeon, Sang-Jin,Kim, Hong-Seok,Cho, Chan-Sik,Shim, Sang-Chul,Kim, Tae-Jeong
, p. 3833 - 3848 (2007/10/03)
A new series of chiral C2-symmetric bisferrocenyldiimine 1 and bisferrocenyldiamines 2 and 3 proved to be efficient ligands for the copper(I)-catalyzed asymmetric cyclopropanation, cyclopropenation, and aziridination of alkenes and alkynes to give high diastereo- and enantioselectivity as well as high chemical yields. In some instances the enantiomeric excesses of cyclopropanated products are among the highest (>97% ee) ever reported. Comparative studies show that stereoselectivity depends highly on the steric variation both in the ligand and the substrate. Other transition metal complexes incorporating some of these ligands such as Ru(3c)Cl2, [(NBD)Rh(2)]ClO4, [Cu(2)(MeCN)2]PF6, and Pd(2)Cl2 also demonstrated high enantioselectivity in cyclopropanation reactions.
CYCLOPROPYL CARBANIONS DERIVED FROM ESTERS OF 2-PHENYLCYCLOPROPYLCARBOXYLIC ACIDS: CONFIGURATIONAL STABILITY AND REACTION WITH ELECTROPHILES
Feit, B. A.,Elser, R.,Melamed, U.,Goldberg, I.
, p. 5177 - 5180 (2007/10/02)
The base-catalyzed cis-trans isomerization of cis and trans-alkyl 2-phenylcyclopropylcarboxylates was studied in several aprotic solvents.It was found that contact ion-pairs of the derived carbanion lithium salts were configurationally more stable than the solvent-separated ones.Reaction of either the cis or the trans esters with Mel, and the reaction of the cis ester with Ph2C=O, resulted in the corresponding 1-substituted derivatives having cis geometry only.This was explained as due to steric hindrance to electrophilic attack exerted by the 2-phenyl group in the case of the trans substrate.The trans esters did not react with Ph2C=O.Inhibition of the trans-to-cis isomerization of the carbanion salt of the trans substrate in presence of Ph2C=O could lead to this result.
AN INTERPRETATION OF THE SUBSTITUENT EFFECT IN THE BLAISE REARRANGEMENT IN TERMS OF PI-ORBITALS
Abe, Yukio,Suehiro, Tadashi
, p. 389 - 392 (2007/10/02)
The migratory aptitude of the substituent groups in the Blaise rearrangement can be explained in terms of the pi-electronic properties of the groups in the highest occupied molecular orbitals.The rates of the rearrangement reaction with relation to the substituent groups were also rationally understood based on the energy levels of the molecular orbitals.
FORMATION OF CYCLOPROPANE DERIVATIVES IN THE BLAISE REARRANGEMENT
Abe, Yukio,Suehiro, Tadashi
, p. 337 - 340 (2007/10/02)
On heating tosylates of ethyl 2-alkyl-2-methyl-3-hydroxy-3-phenylpropanoate (R=Me, 1b; R=Et, 6) in o-dichlorobenzene at 170 deg C, ethyl 1- methyl-2-phenyl- and 1,2-dimethyl-3-phenylcyclopropanecarboxylates, 3, and 8, were formed in both 5percent yield, respectively, whereas the alkyl migration products, ethyl 3-alkyl-2-methyl-3-phenylpropenoates, were not produced.The mode of the reaction of the methyl group with the cationic carbon was described.
