No abstract

[reaction: see text] Polymer-supported bisBINOL ligands were successfully utilized for the immobilization of multicomponent asymmetric catalysts. The polymer-supported Al-Li-bis(binaphthoxide) (ALB) catalyst was more effective than the dendrimer-supported ALB in the Michael reaction of 2-cyclohexen-1-one with dibenzyl malonate affording the adduct in 91% yield with 96% ee. The polymer was also effective for the immobilization of a mu-oxodititanium complex that promoted carbonyl-ene reaction of ethyl glyoxalate with alpha-methyl styrene to provide the adduct with up to 98% ee.

Big MAC news! A new concept for constructing multicomponent asymmetric catalysts (MACs) is proposed by use of a stable “catalyst analogue”. After copolymerization of a catalyst analogue having olefinic moieties with a monomer (e.g., methyl methacrylate), the resulting polymer is used to prepare an active catalyst by exchanging the connecting group with a catalytically active metal (see scheme).

Die Verwendung eines stabilen Katalysator‐Analogons öffnet einen neuen Zugang zu asymmetrischen Mehrkomponenten‐Katalysatoren (MACs). Nach Copolymerisation der olefinischen Einheiten dieses Katalysator‐Analogons mit einem Monomer (z. B. Methylmethacrylat) erhält man das aktive Katalysator‐Polymer durch Austausch der verbindenden Gruppen gegen katalytisch aktive Metallzentren (siehe Schema).