100190-34-9Relevant articles and documents
Effect of amine structure and reaction additives on enantioselective deprotonations mediated by homochiral magnesium amide bases
Anderson, John D,García García, Pilar,Hayes, Douglas,Henderson, Kenneth W.,Kerr, William J.,Moir, Jennifer H.,Fondekar, Kamalesh Pai
, p. 7111 - 7114 (2001)
A series of novel, optically pure, Mg-bisamides have been prepared and, in turn, used to mediate enantioselective deprotonations of conformationally locked ketones. The new bases exhibit a wide range of selectivities, from poor to excellent (up to 95:5 e.
Optimisation of a lithium magnesiate for use in the non-cryogenic asymmetric deprotonation of prochiral ketones
Francos, Javier,Zaragoza-Calero, Silvia,O'Hara, Charles T.
, p. 1408 - 1412 (2014)
A study has been conducted to determine whether lithium magnesiates are feasible candidates for the enantioselective deprotonation of 4-alkylcyclohexanones. The commercially available chiral amine (+)-bis[(R)-1-phenylethyl]amine (2-H) was utilised to indu
Novel enantiomerically pure heteroleptic magnesium complexes for use in enantioselective deprotonation reactions
Carswell, Emma L.,Hayes, Douglas,Henderson, Kenneth W.,Kerr, William J.,Russell, Claire J.
, p. 1017 - 1021 (2003)
Two classes of heteroleptic magnesium complexes, alkylmagnesium amides RMgNR2 and aryloxymagnesium amides ROMgNR2, have been prepared and subsequently shown to be efficient bases in the enantioselective deprotonation of substituted c
An Enhancement of Enantioselectivity in Chiral Lithium Amide Deprotonations Due to Lithium Chloride
Bunn, Barry J.,Simpkins, Nigel S.
, p. 533 - 534 (1993)
Substantial improvements in the enantiomeric excess of products obtained from chiral base-mediated reactions of prochiral ketones under external quench (EQ) conditions are observed if the deprotonation is carried out in the presence of added LiCl.
Stereoselective reactions. 29. Lithium-hydrogen interchange between achiral tridentate lithium amides and chiral bidentate amines. An approach to catalytic enantioselective
Yamashita, Toyoharu,Sato, Daisaku,Kiyoto, Taro,Kumar, Arvind,Koga, Kenji
, p. 16987 - 16998 (1997)
1H-NMR spectral studies have shown that lithium-hydrogen interchange between a chiral bidentate amine ((R)-3b) and an achiral tridentate lithium amide (5a) occurs rapidly in THF, favoring the exclusive formation of a chiral bidentate lithium am
Towards energetically viable asymmetric deprotonations: Selectivity at more elevated temperatures with C2-symmetric magnesium bisamides
Bennie, Linsey S.,Kerr, William J.,Middleditch, Michael,Watson, Allan J. B.
, p. 2264 - 2266 (2011)
A novel chiral magnesium bisamide has enabled the development of effective asymmetric deprotonation protocols at substantially more elevated temperatures. This new, structurally simple, C2-symmetric magnesium complex displays excellent levels o
Stereoselective reactions. XXXIV. Enantioselective deprotonation of prochiral 4-substituted cyclohexanones using chiral bidentate lithium amides having a bulky group instead of a phenyl group on the chiral carbon
Toriyama,Sugasawa,Motohashi,Tokutake,Koga
, p. 468 - 472 (2001)
Using chiral bidentate lithium amides having a bulky group instead of a phenyl group on the chiral carbon, enantioselective deprotonation of prochiral 4-substituted cyclohexanones in the presence of excess trimethylsilyl chloride was examined in THF in th
Enantioselective deprotonation of 4-tert-butylcyclohexanone by fluorine-containing chiral lithium amides derived from α-phenethylamine
Aoki, Kazumasa,Koga, Kenji
, p. 2505 - 2506 (1997)
An α-phenethylamine-derived chiral lithium amide ((R)-5c) possessing a 2,2,2-trifluoroethyl group on the amide nitrogen was found to induce high enantioselectivity in the kinetic deprotonation of 4-tert-butylcyclohexanone (1) in the presence of excess tri
Enantioselective deprotonation reactions using polymer-supported chiral magnesium amide bases
Henderson,Kerr,Moir
, p. 1722 - 1723 (2001)
Novel and readily accessible polymer-supported chiral magnesium amide reagents have been prepared and shown to be effective in the asymmetric deprotonation of a series of prochiral cyclohexanones, affording good to excellent levels of both conversion and
Stereoselective reactions. XXVII. Solution structures of a chiral tridentate lithium amide in relation to enantioselective deprotonation of 4- tert-butylcyclohexanone
Sato, Daisaku,Kawasaki, Hisashi,Koga, Kenji
, p. 1399 - 1402 (1997)
6Li- and 15N-NMR spectroscopic StUdies on the solution structures of a chiral tridentate lithium amide have revealed that it exists as a chelated monomer in which the lithium is tri-coordinated, as a chelated dimer in which the lithi
Stereochemistry of enantioselective deprotonation of 4-substituted cyclohexanones by chiral bidentate lithium amides
Toriyama, Masaharu,Sugasawa, Keizo,Shindo, Mitsuru,Tokutake, Norio,Koga, Kenji
, p. 567 - 570 (1997)
Enantioselective deprotonation of 4-substituted cyclohexanones (1) in the presence of excess trimethylsilyl chloride was examined using chiral bidentate lithium amides ((R)-3~(R)-7 in THF. The solution structure of (R)-3a in THF in the presence and in the
Magnesium amide base-mediated enantioselective deprotonation processes
Henderson, Kenneth W,Kerr, William J,Moir, Jennifer H
, p. 4573 - 4587 (2002)
A novel homochiral magnesium bisamide has been readily prepared and, following careful optimisation, this species has been shown to react efficiently with a series of prochiral 4-substituted cyclohexanones in the presence of TMSCl to give the corresponding silyl enol ethers in enantiomeric ratios of up to 95:5. Additionally, the same chiral base system has been shown to be highly effective in the desymmetrisation of cis-2,6-disubstituted cyclohexanones, providing excellent levels of both conversion and enantioselection (up to >99.5:0.5 er). Furthermore, the magnesium bisamide has also been shown to mediate a kinetic resolution process with the corresponding trans-disubstituted substrates, allowing access to enantioenriched enol ethers and ketones.
Development of chiral heteroleptic magnesium amides; Asymmetric deprotonations mediated by six-membered metallocyclic amidomagnesium naphtholates
Carswell, Emma L.,Kerr, William J.,McArthur, Duncan,Pa?icky, Marek,Watson, Allan J.B.
, p. 7344 - 7349 (2016/01/25)
A series of enantioenriched six-membered metallocyclic amidomagnesium naphtholates were prepared and used to probe the structure-reactivity/selectivity relationships of heteroleptic magnesium base complexes within asymmetric deprotonation reactions. An ef
