Stereocontrol in asymmetric phospho-aldol catalysis. Chirality relaying in action

Nixon, Tracy D.; Dalgarno, Scott J.; Ward, Caroline V; Jiang, Mingliang; Halcrow, Malcolm A.; Kilner, Colin A.; Thornton‐Pett, Mark; Kee, Terence P.

doi:10.1016/j.crci.2003.10.020

Cited by 29 publications

(3 citation statements)

References 34 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…For example, a mixed pyridyl(imino)(amido) aluminum(III) compound derived from treatment of the parent 2,6-bis(imino)pyridine ligand with AlMe 3 reported by Bruce and coworkers [35] exhibits a short, deprotonated N amido –Al distance = 1.876(4) Å. These Al III -N bonds are significantly shorter than the Zn II -N (2.202(2); 2.173(2) Å) and Fe II -N (2.188(2); 2.184(2) Å) bond lengths observed in 1 and [Fe II (LN 3 S)(OTf)], respectively [27], or the Al III -N(H)RR’ bond lengths of 2.090(5) and 2.098(5) Å seen in the complex [(( R , R )-R 4 -salcyan)Al(OH)] [36], where the amine donor is protonated. Furthermore, the Al III -S distance in 2a (2.2798(9) Å) falls in the reported range for other Al III -SR bond lengths (2.220(1) to 2.5226(6) Å) [37–39].…”

Section: Resultsmentioning

confidence: 99%

Preparation of aluminum(III) (bis(amido)pyridine)(thiolate) complexes: Unexpected transmetalation mediated by LiAlH4

Badiei¹,

Jiang²,

Widger³

et al. 2012

Inorganica Chimica Acta

View full text Add to dashboard Cite

Treatment of an unsymmetrical bis(imino)pyridyl-thiolate zinc(II) complex [ZnII(LN3S)(OTf)] (1) with LiAlH4 results in the double reduction of the two imino groups in the ligand backbone, and at the same time causes a rare transmetalation reaction to occur. The products formed in this reaction are two novel aluminium(III) bis(amido)pyridyl-thiolate complexes [(R,S/S,R-[AlIII(LH2N3S)(THF)] (2a) and [(R,R/S,S-[AlIII(LH2N3S)(THF)] (2b), which are diastereomers of each other. These complexes have been characterized by single-crystal X-ray diffraction and 1H NMR spectroscopy. Single crystal X-ray structure analysis shows that the AlIII ion is bound in an almost idealized square pyramidal geometry in 2a, while being held in a more distorted square pyramidal geometry in 2b. The major difference between 2a and 2b arises in the orientation of the terminal methyl groups of the ligand backbone in relation to the AlIIIN3S plane. These two complexes are crystallized at different temperatures (room temperature vs −35 °C), allowing for their separate isolation. Structural analysis shows that these complexes are reduced by the formal addition of one hydride ion to each imino group, resulting in a deprotonated bis(amido)pyridyl-thiolate ligand. A detailed analysis of metrical parameters rules out the possibility of pure one- or two-electron reduction of the π-conjugated bis(imino)pyridine framework. 1H NMR spectra reveal a rich pattern in solution indicating that the solution state structures for 2a and 2b match those observed in the solid-state crystal structures, and reveal that both complexes are severely conformationally restricted. Direct organic synthetic methods failed to produce the reduced bis(amino)pyridyl-thiol ligand in pure form, but during the course of these efforts an unusual unsymmetrical aminopyridyl ketone, 1-(6-(1-(2,6-diisopropylphenylamino)ethyl)pyridin-2-yl)ethanone was synthesized in good yield and can be used as a possible precursor for further ligand development.

show abstract

Section: Resultsmentioning

confidence: 99%

Preparation of aluminum(III) (bis(amido)pyridine)(thiolate) complexes: Unexpected transmetalation mediated by LiAlH4

Badiei¹,

Jiang²,

Widger³

et al. 2012

Inorganica Chimica Acta

View full text Add to dashboard Cite

show abstract

“…Os alcalóides derivados da Cinchona, em especial a quinina e seus derivados, têm sido muito utilizados para a determinação de excessos enantioméricos de compostos pertencentes a várias funcionalidades, como por exemplo: -hidróxi ésteres 34,35 , mono-e di-hidróxi-hidróxi-fosfonatos [36][37][38][39] (RMN de P-31), hidróxi-fosfonatos trifluorometilados 40,41…”

Section: Alcalóides E Seus Derivados Como Discriminadores Quiraisunclassified

“…A terceira e última amida testada foi uma molécula contendo somente um anel aromático, ao invés de três anéis como as amidas anteriores. De fato, é comum encontrarmos na literatura relatos da utilização bem sucedida da quinina como agente de discriminação quiral para compostos quirais que possuam um ou mais grupos hidroxila, como os di-hidróxifosfonatos [36][37][38][39] , hidróxi-fosfonatos trifluorometilados 40,41 e ésteres hidroxilados 34,35 .…”

Section: N-metil-n-fenil-2-metilbutanamida (42)unclassified

Estudos por RMN de 1H das interações de substratos carbonílicos e carboxílicos com agentes de discriminação quiral

Claudio¹

View full text Add to dashboard Cite

show abstract

Coordination Chemistry and Applications of Salen, Salan and Salalen Metal Complexes

Bellemin‐Laponnaz

Dagorne

2012

Patai's Chemistry of Functional Groups

View full text Add to dashboard Cite

The present contribution summarizes and highlights the essential coordination features and applications of salen‐supported metal complexes. The use of salen complexes in homogeneous (and asymmetric) catalysis constitutes a major part of this chapter as salen‐type (and closely related) ligands have undoubtedly established themselves as “privileged” supporting ligands in catalysis over the past 20 years. The interest of such tetradentate chelating ligands in various other applications, including the suitability of salen metal complexes for medical applications and as building blocks for the synthesis of well‐defined polymetallic assemblies, will also be briefly discussed.

show abstract

Stereocontrol in asymmetric phospho-aldol catalysis. Chirality relaying in action

Cited by 29 publications

References 34 publications

Preparation of aluminum(III) (bis(amido)pyridine)(thiolate) complexes: Unexpected transmetalation mediated by LiAlH4

Preparation of aluminum(III) (bis(amido)pyridine)(thiolate) complexes: Unexpected transmetalation mediated by LiAlH4

Estudos por RMN de 1H das interações de substratos carbonílicos e carboxílicos com agentes de discriminação quiral

Coordination Chemistry and Applications of Salen, Salan and Salalen Metal Complexes

Contact Info

Product

Resources

About