100007-62-3Relevant academic research and scientific papers
A new strategy for designing non-C2-symmetric monometallic bifunctional catalysts and their application in enantioselective cyanation of aldehydes
Yang, Fei,Wei, Siping,Chen, Chien-An,Xi, Peihua,Yang, Li,Lan, Jingbo,Gau, Han-Mou,You, Jingsong
, p. 2223 - 2231 (2008)
A monometallic bifunctional catalyst, in which only one imidazolyl moiety is directly attached at the 3-position of a binaphthol moiety, has been developed. The ligand (R)-1, which lacks C2-symmetry and flexible linkers, in combination with Ti(OiPr)4, has been demonstrated to promote the enantioselective cyanation of aldehydes with trimethylsilylcyanide (TMSCN), giving excellent enantioselectivities of up to 98 % ee and high yields of up to 99%. The use of this bifunctional catalytic system obviates the need for additives and is extremely simple as the reagents are added in one portion at the beginning of the reaction. The protocol has been found to tolerate a relatively wide range of aldehydes when 10 mol% of the (R)-1/Ti(OiPr) 4 complex is deployed in CH2Cl2 at -40°C, the conditions which proved most practical and effective. The asymmetric cyanations also proceeded with lower catalyst loadings (5 mol%, or even 2 mol%), still giving satisfactory enantiomeric excesses and yields. Interestingly, the use of freshly distilled TMSCN dried over CaH2 gave a low enantioselectivity and only a moderate yield of the adduct as compared with direct use of the commercial reagent. The results of 13C NMR spectroscopic studies implicate HCN as the actual reactive nucleophile.
Copper-Catalyzed Substitution of α-Triflyloxy Nitriles and Esters with Silicon Nucleophiles under Inversion of the Configuration
Scharfbier, Jonas,Hazrati, Hamideh,Irran, Elisabeth,Oestreich, Martin
, p. 6562 - 6565 (2017)
A copper-catalyzed nucleophilic displacement of α-triflyloxy nitriles and esters with silicon nucleophiles allows for the stereospecific generation of highly enantioenriched α-silylated carboxyl compounds. The enantioselective synthesis of α-silylated nitriles is unprecedented. The catalytic system exhibits good functional group tolerance. The stereochemical course of the substitution is shown to proceed with inversion of the configuration. The new reaction is an addition to the still limited number of methods for catalytic C(sp3)-Si cross-coupling.
Asymmetric trimethylsilylcyanation of aldehydes utilizing chiral bismuth compounds. A frontier in bismuth mediated synthetic reactions
Wada, Makoto,Takahashi, Toshikazu,Domae, Terutomo,Fukuma, Tomohiro,Miyoshi, Norikazu,Smith, Keith
, p. 3939 - 3946 (1997)
Bismuth(III) chloride (BiCl3) was found to work efficiently as a versatile catalyst for cyanation of aldehydes with trimethylsilyl cyanide to afford the corresponding cyanohydrins in high yields. Triphenylbismuthan (Ph3Bi) is also effective. The reaction has been applied to the asymmetric cyanation of a variety of aldehydes in high yields with moderate to good enantioselectivities by use of a chiral bismuth catalyst prepared in situ from BiCl3 and (2R,3R)-(+)-diethyl tartrate.
Enzyme catalysed formation of (S)-cyanohydrins derived from aldehydes and ketones in a biphasic solvent system
Griengl, Herfried,Klempier, Norbert,Poechlauer, Peter,Schmidt, Michael,Shi, Nongyuan,Zabelinskaja-Mackova, Antonina A.
, p. 14477 - 14486 (1998)
By employing a vigorously stirred two phase system aqueous buffer/organic solvent and using the hydroxynitrile lyase from Hevea brasiliensis as biocatalyst enantiopure (S)-cyanohydrins from aliphatic, unsaturated, aromatic and heteroaromatic aldehydes and methyl alkyl and methyl phenyl ketones are obtained in high yield and in general 98-99% enantiomeric excess.
Enantioselective trimethylsilylcyanation of aldehydes
Bolm, Carsten,Mueller, Peter
, p. 1625 - 1628 (1995)
A chiral titanium reagent derived from optically active sulfoximine (R)-3 and Ti(O-i-Pr)4 promotes the asymmetric addition of trimethylsilylcyanide to aldehydes affording cyanohydrins in high yields with good enantioselectivities (up to 91% ee).
Catalysis of aldehyde and imine silylcyanation by platinum and palladium NCN-pincer complexes
Fossey, John S.,Richards, Christopher J.
, p. 8773 - 8776 (2003)
The room temperature addition of trimethylsilylcyanide to aromatic and aliphatic aldehydes to give the corresponding cyanohydrins is efficiently catalysed by 1 mol% of ((2,6-bis(N-cyclohexyl)imino)phenyl)aquoplatinum(II) trifluoromethanesulfonate 1a. This methodology is also applicable to the addition of trimethylsilylcyanide to Schiff bases resulting in the formation of α-amino nitriles.
Cyanosilylation of aldehydes catalyzed by N-heterocyclic carbenes
Suzuki, Yumiko,Bakar, M.D., Abu,Muramatsu, Kazuyuki,Sato, Masayuki
, p. 4227 - 4231 (2006)
N-Heterocyclic carbenes produced in situ from salts of imidazolium, benzimidazolium, pyrido[1,2-c]imidazolium, imidazolinium, thiazolium, and triazolium catalyze the addition of trimethylsilylcyanide to aldehydes to yield cyanohydrin trimethylsilyl ethers. The use of C2-symmetric imidazolidenyl carbene derived from (R,R)-1,3-bis[(1-naphthyl)ethyl]imidazolium chloride led to enantioselective cyanosilylation.
Mechanism-Based inactivation of human cytochrome p450 3A4 by two piperazine-Containing compounds
Bolles, Amanda K.,Fujiwara, Rina,Briggs, Erran D.,Nomeir, Amin A.,Furge, Laura Lowe
, p. 1471 - 1475 (2014)
Human cytochrome P450 3A4 (CYP3A4) is responsible for the metabolism of more than half of pharmaceutic drugs, and inactivation of CYP3A4 can lead to adverse drug-drug interactions. The substituted imidazole compounds 5-fluoro-2-[4-[(2-phenyl-1H-imidazol-5-yl) methyl]-1-piperazinyl]pyrimidine (SCH 66712) and 1-[(2-ethyl-4-methyl-1H-imidazol-5-yl)methyl]-4-[4-(trifluoromethyl)-2-pyridinyl]piperazine (EMTPP) have been previously identified as mechanism-based inactivators (MBI) of CYP2D6. The present study shows that both SCH 66712 and EMTPP are also MBIs of CYP3A4. Inhibition of CYP3A4 by SCH 66712 and EMTPP was determined to be con-centration, time, and NADPH dependent. In addition, inactivation of CYP3A4 by SCH 66712 was shown to be unaffected by the presence of electrophile scavengers. SCH 66712 displays type I binding to CYP3A4 with a spectral binding constant (Ks) of 42.9 ± 2.9 μM. The partition ratios for SCH 66712 and EMTPP were 11 and 94, respectively. Whole protein mass spectrum analysis revealed 1:1 binding stoichiometry of SCH 66712 and EMTPP to CYP3A4 and a mass increase consistent with adduction by the inactivators without addition of oxygen. Heme adduction was not apparent. Multiple monooxygenation products with each inactivator were observed; no other products were apparent. These are the first MBIs to be shown to be potent inactivators of both CYP2D6 and CYP3A4.
Enantioselective synthesis of aliphatic cyanohydrin acetates
Veum, Lars,Hanefeld, Ulf
, p. 2382 - 2384 (2005)
When the standard conditions for the enantioselective synthesis of cyanohydrin acetates via dynamic kinetic resolution are applied to aliphatic substrates, only a kinetic resolution is observed. However, by exchanging the base (Amberlite) against NaCN, qu
Development of β-hydroxyamide/titanium complexes for catalytic enantioselective silylcyanation of aldehydes
Uang, Biing-Jiun,Fu, I-Pin,Hwang, Chyuan-Der,Chang, Chun-Wei,Yang, Chun-Tzu,Hwang, Der-Ren
, p. 10479 - 10486 (2004)
A highly enantioselective addition of trimethylsilylcyanide to aldehydes catalyzed by chiral titanium complexes is described. The chiral titanium complexes were prepared in situ from Ti(OiPr)4 and β-hydroxyamide ligands, that could easily be synthesized from ketopinic acid and C2 symmetrical chiral diamines in a small number of steps. Graphical Abstract.
