174814-83-6Relevant academic research and scientific papers
Highly enantioselective Michael reactions catalyzed by a chiral quaternary ammonium salt. Illustration by asymmetric syntheses of (S)-ornithine and chiral 2-cyclohexenones.
Zhang,Corey
, p. 1097 - 1100 (2000)
[formula: see text] The use of the chiral quaternary ammonium salts 1a and 1b makes possible enantioselective Michael reactions which have been applied to the asymmetric syntheses of (S)-ornithine (2) and the chiral 2-cyclohexenone 6.
Transformations of isoxazolidine and dihydropyran derivatives to optically active compounds
Diaz-Ortiz, Angel,Diez-Barra, Enrique,De La Hoz, Antonio,Prieto, Pilar,Moreno, Andres
, p. 259 - 263 (1996)
Isoxazolidine and dihydropyran spiro derivatives can be easily transformed, by hydrolysis and hydrogenolysis, to give δ-keto esters, δ-keto acids, β-amino esters, β-amino acids and 3-amino alcohols in good yields. Starting from optically active compounds
Enantioselective Mukaiyama-Michael reaction of silyl enol ethers to 2-enoylpyridine N-oxides catalyzed by copper-bis(oxazoline) complex
Georgea, Jimil,Reddy, Basi V. Subba
supporting information, p. 383 - 388 (2013/05/08)
A catalytic enantioselective Mukaiyama-Michael reaction of 2-enoylpyridine N-oxides has been developed using a simple bis(oxazoline)-copper complex. A variety of silyl enol ethers undergo smooth Michael addition with 2-enoylpyridine N-oxides to furnish the corresponding Michael adducts in high yields with high enantioselectivities (up to 97% ee).
Ligand differentiated complementary Rh-catalyst systems for the enantioselective desymmetrization of meso-cyclic anhydrides
Johnson, Jeffrey B.,Cook, Matthew J.,Rovis, Tomislav
supporting information; experimental part, p. 3202 - 3210 (2009/08/15)
Two distinct systems for the rhodium-catalyzed enantioselective desymmetrization of meso-cyclic anhydrides have been developed. Each system has been optimized and are compatible with the use of in situ prepared organozinc reagents. Rhodium/PHOX species efficiently catalyze the addition of alkyl nucleophiles to glutaric anhydrides, while a rhodium/phosphoramidite system is effective in the enantioselective arylation of succinic and glutaric anhydrides.
Diphenylprolinol silyl ether as a catalyst in an enantioselective, catalytic, formal aza [3+3] cycloaddition reaction for the formation of enantioenriched piperidines
Hayashi, Yujiro,Gotoh, Hiroaki,Masui, Ryouhei,Ishikawa, Hayato
supporting information; experimental part, p. 4012 - 4015 (2009/02/08)
(Chemical Presented) Aza-ene reaction: Diphenylprolinol silyl ether was found to be an effective organocatalyst for the formal aza [3+3] cycloaddition reaction of a,b-unsaturated aldehydes and enecarbamates (see scheme). The reaction proceeds through an asymmetric catalytic ene reaction, isomerization, hydrolysis, and cyclization to afford piperidine derivatives in good yields and excellent enantioselectivities.
N-heterocyclic carbene catalyzed C-C bond cleavage in redox esterifications of chiral formylcyclopropanes
Sohn, Stephanie S.,Bode, Jeffrey W.
, p. 6021 - 6024 (2007/10/03)
(Chemical Equation Presented) A clean break: An N-heterocyclic carbene catalyzes the ring-opening of chiral non-racemic formylcyclopropanes, with simultaneous oxidation of the aldehyde function and without the need for stoichiometric reagents. The activated carboxylate intermediate is trapped by a variety of nucleophiles, thus leading to chiral esters, thioesters, or carboxylic acids (see scheme; DBU = 1,8-diazabicyclo-[5.4.0]undec-7-ene, EWG = electron-withdrawing group, Nu = nucleophile.)
Highly enantioselective desymmetrization of anhydrides by carbon nucleophiles: Reactions of Grignard reagents in the presence of (-)-sparteine
Shintani, Ryo,Fu, Gregory C.
, p. 1057 - 1059 (2007/10/03)
Where other common chiral ligands failed, (-)-sparteine can be employed to form complexes with Grignard reagents. These chirally modified reagents desymmetrize a range of anhydrides with good enantioselectivity (up to 92% ee; see scheme). Whereas (-)-sparteine is well known to form complexes with organolithium reagents and to induce excellent enantioselection in their reactions with electrophiles, (-)-sparteine-controlled asymmetric processes that involve Grignard reagents are rare.
