Li₃[Ln(binol)₃]·6THF:  New Anhydrous Lithium Lanthanide Binaphtholates and Their Use in Enantioselective Alkyl Addition to Aldehydes

Abstract

Anhydrous lithium lanthanide binaphtholates have been prepared by reaction of lanthanide tris(silylamides) with 3 equiv of LiHbinol. Li3[Y(R-binol)3]·6THF has been characterized by single-crystal X-ray diffraction, and Li3[La(S-binol)3]·6THF has been shown to be an effective reagent for the enantioselective addition of MeLi to a range of aldehydes.

Chirale Gallium- und Indium-Alkoxometallate

“…So ko È nnen je nach Zentralmetall spezielle enantioselektive katalytische Reaktionen ausgefu È hrt werden. [{Li(THF) 2 } 3 {Al(BINOLat) 3 }] dient in einer asymmetrischen Horner-WadsworthEmmons-Reaktion [1 a] und [Na{Ga(BINOLat) 2 }] zusammen mit 4-Methoxy-phenol in Ringo È ffnungen als Katalysator [2]. Mit den Lanthanoid-Komplexen [{Li(THF) 2 } 3 {Ln(BINOLat) 3 }] und MeLi wird eine enantioselektive Addition an Aldehyde beobachtet [3].…”

“…[{Li(THF) 2 } 3 {Al(BINOLat) 3 }] dient in einer asymmetrischen Horner-WadsworthEmmons-Reaktion [1 a] und [Na{Ga(BINOLat) 2 }] zusammen mit 4-Methoxy-phenol in Ringo È ffnungen als Katalysator [2]. Mit den Lanthanoid-Komplexen [{Li(THF) 2 } 3 {Ln(BINOLat) 3 }] und MeLi wird eine enantioselektive Addition an Aldehyde beobachtet [3]. Strukturuntersuchungen wurden ebenfalls an [{(THF) 3 Li}{Al(BINOLat) 2 Bemerkenswert ist, daû fu È r die katalytisch aktive Spezies der Al-und Ga-Derivate von vierfach koordinierten Metallzentren ausgegangen wird [1,2], da nur bei Koordinationszahl (KZ) fu È nf oder niedriger des Zentralmetalls mit einer Edukt-Addition zu rechnen ist.…”

“…GaCl 3 [19], InCl 3 [19] und Ga(CH 2 Ph) 3 [20] wurden nach Literaturvorschrift dargestellt. [{Li(THF) 2 }{Li(THF)} 2 {Ga((S)-BINOLat) 3 Kristallstrukturen von 1´2 Toluol ± 3´8 Toluol Fu È r die Ro È ntgenstrukturanalyse geeignete Kristalle wurden unter einem Ku È hlgasstrom von N 2 mittels eines perfluorierten Polyethers auf einer Glaskapillare befestigt und die Zellparameter sowie Reflexintensita È ten bestimmt. Zur Darstellung der Bindungsla È ngen und -winkel, Berechnung von U eq und Zeichnung der Moleku È lstrukturen wurden die Programme PLATON-98 [21] und SHELXTL [22] verwendet.…”

Lithium Binaphtholates: Chiral Chains and Clusters

“…[7,8] In addition to these applications in asymmetric synthesis, binaphthol has also been of interest as a component of macrocycles for chiral recognition, [9,10] and as a component of helical polymers with novel properties such as the emission of polarized light. [13] Our interest in lithium binaphtholates arose from our use of LiHbinol in the synthesis of anhydrous analogues of Shibasakis heterometallic catalysts, [14] and herein we report on investigations of mono-and dilithiated derivatives of optically pure and racemic H 2 binol. Lithiated H 2 binol has been used in the preparation of many enantioselective catalysts and has also been investigated as a chiral auxiliary in its own right.…”

“…[1] The flexibility of the dihedral angle between the two naphthyl rings of this C 2symmetric molecule allows coordination to a wide range of metal centers (examples are known from 458 to 1108), and H 2 binol has been used as a chiral auxiliary in many metal-based enantioselective catalysts and reagents. [13] Our interest in lithium binaphtholates arose from our use of LiHbinol in the synthesis of anhydrous analogues of Shibasakis heterometallic catalysts, [14] and herein we report on investigations of mono-and dilithiated derivatives of optically pure and racemic H 2 binol. [4] Multi-binaphthol species have attracted recent interest; particularly successful examples are Mikamis Ti ± binaphtholate catalysts [5] and the heterometallic alkali metal/ lanthanide binaphtholates synthesised by Shibasaki et al [6] Examples of catalytically active multi-binaphthol Ti clusters have also been reported.…”