59614-85-6Relevant academic research and scientific papers
CuH-Catalyzed Asymmetric Conjugate Reductions of Acyclic Enones
Lipshutz, Bruce H.,Servesko, Jeff M.
, p. 4789 - 4792 (2003)
A powerful new reaction has been developed for the asymmetric 1, 4-reduction of prochiral enones (see scheme). The key ingredients in this exceedingly mild and straightforward procedure are catalytic quantities of CuH, a readily available nonracemic phosphane ligand such as that shown, and inexpensive polymethyl-hydrosiloxane (PMHS) as the stoichiometric source of hydride.
Neutral iridium catalysts with chiral phosphine-carboxy ligands for asymmetric hydrogenation of unsaturated carboxylic acids
Yang, Shuang,Che, Wen,Wu, Hui-Ling,Zhu, Shou-Fei,Zhou, Qi-Lin
, p. 1977 - 1980 (2017/03/09)
We developed neutral iridium catalysts with chiral spiro phosphine-carboxy ligands (SpiroCAP) for asymmetric hydrogenation of unsaturated carboxylic acids. Different from the cationic Crabtree-type catalysts, the iridium catalysts with chiral spiro phosphine-carboxy ligands are neutral and do not require the use of a tetrakis[3,5-bis(trifluoromethyl)phenyl]borate (BArF?) counterion, which is necessary for stabilizing cationic Crabtree-type catalysts. Another advantage of the neutral iridium catalysts is that they have high stability and have a long lifetime in air. The new iridium catalysts with chiral spiro phosphine-carboxy ligands exhibit unprecedented high enantioselectivity (up to 99.4% ee) in the asymmetric hydrogenations of various unsaturated carboxylic acids, particularly for 3-alkyl-3-methylenepropionic acids, which are challenging substrates for other chiral catalysts.
Syntheses of (R)- and (S)-3-methylheptanoic acids
Zhang, Shunji,Shi, Yong,Tian, Weisheng
supporting information, p. 674 - 678 (2015/06/25)
Starting from chiral methyl molecules 3 and 4, both derived from (R)-4-methyl-δ-valerolactone, we have accomplished the synthesis of (R) and (S)-3-methylheptanoic acids. Our methods are amendable to the syntheses of a wide variety of chiral 3-methyl alkanoic acids. Both enantiomers of 3-methylheptanoic acid have been synthesized from chiral methyl molecules which were derived from (R)-4-methyl-δ-valerolactone (5). A wide variety of chiral 3-methyl alkanoic acids can also be synthesized by the methods described herein.
Applications of enantioselective carbolithiation of ortho-substituted β-methylstyrenes
Hogan, Anne-Marie L.,Tricotet, Thomas,Meek, Alastair,Khokhar, Shaista S.,O'Shea, Donal F.
, p. 6041 - 6044 (2008/12/21)
(Chemical Equation Presented) The enantioselective carbolithiation of ortho-substituted (E)-β-methylstyrenes provides access to chiral lithiated intermediates with broad synthetic potential. Specifically, β- methylstyrenes with o-aminomethyl, ether, and o
Anthracene cycloadducts as highly selective chiral auxiliaries
Liu, Xiang,Snyder, John K.
, p. 2935 - 2938 (2008/09/19)
(Chemical Equation Presented) A new chiral auxiliary was designed and easily prepared from a Diels-Alder cycloadduct of an enantiomerically pure anthracene with maleimide. Excellent diastereoselectivities in Diels-Alder reactions, conjugate additions, and aldol reactions employing these auxiliaries are now reported.
Asymmetric cascade reaction sequences via chiral lithiated intermediates
Hogan, Anne-Marie L.,O'Shea, Donal F.
, p. 2503 - 2509 (2008/09/19)
(Chemical Equation Presented) The (-)-sparteine-mediated enantioselective intermolecular carbolithiation of (E)-2-propenylarylamines allows for the generation of chiral lithiated intermediates which have broad synthetic potential. These intermediates have been exploited in a series of further in situ reactions with electrophiles to generate a collection of products each containing a common stereogenic center. The stereogenic center, formed in high enantiomeric ratio in the first carbolithiation step, is carried through the cascade reaction sequence to the final products and is independent of electrophile used. The methodology is demonstrated by the synthesis of structurally diverse chiral anilines, indoles, and indolones all with an er of 92:8 (±1). The heterocyclic syntheses involve an enantioselective alkene carbolithiation and subsequent trapping of the intermediate organolithium with a suitable electrophile, followed by an in situ ring closure and dehydration to generate the indole or indolone rings.
Rh-catalyzed highly enantioselective synthesis of 3-arylbutanoic acids
Sun, Xianfeng,Zhou, Le,Wang, Chun-Jiang,Zhang, Xumu
, p. 2623 - 2626 (2008/02/13)
(Chemical Equation Presented) It's in the mix: The reaction conditions - catalyst, additive, and solvent - have been optimized for the asymmetric hydrogenation of 3-aryl-3-butenoic acids. The rigid, chiral bisphospholane ligand (SP,RC)-DuanPhos is crucial to achieving high enantioselectivity.
(S,S)-(+)-pseudoephedrine as chiral auxiliary in asymmetric conjugate addition and tandem conjugate addition/α-alkylation reactions
Reyes, Efraim,Vicario, Jose L.,Carrillo, Luisa,Badia, Dolores,Uria, Uxue,Iza, Ainara
, p. 7763 - 7772 (2007/10/03)
(Chemical Equation Presented) Organolithium reagents undergo highly regio- and diastereoselective 1,4-addition to (S,S)-(+)-pseudoephedrine enamides furnishing the corresponding β-alkyl-substituted adducts in excellent yields and diastereoselectivities. In addition, the intermediate lithium enolates generated after the conjugate addition step undergo a highly diastereoselective alkylation reaction, furnishing α,β-dialkyl- substituted amides in high yields. The obtained adducts have been converted into chiral nonracemic β-alkyl- and α,β-dialkyl-substituted carboxylic acids and γ-alkyl- and β,γ-dialkyl-substituted alcohols using very simple and high-yielding procedures.
(R)-4-menthenone in the synthesis of optically pure sex pheromone of the peach leafminer moth (Lyonetia clerkella)
Kharisov,Latypova,Talipov,Muslukhov,Ishmuratov,Tolstikov
, p. 2267 - 2269 (2007/10/03)
The synthesis of (14S)-methyloctadec-1-ene, sex pheromone of the peach leafminer moth (Lyonetia clerkella), is described to demonstrate a new potential of the synthetic use of (R)-4-menthenone.
The 1,4-addition of organometallic reagents to enoates derived from pinanediol
Pinheiro, Sergio,Pedraza, Sergio F.,Peralta, Monica A.,Teixeira, Rafael C.,De Farias, Florence M. C.,Ferreira, Vitor F.,Costa, Paulo R. R.
, p. 2513 - 2517 (2007/10/03)
The complex-induced, proximity effect-promoted 1,4-addition of RCu·BF3 and R2CuLi to enoates derived from (-)-pinanediol leads to adducts with the opposite sense of chirality (up to 98% d.e.).
