title: Asymmetric Copper-Catalyzed Vinylogous Mukaiyama Michael Addition of Cyclic Dienol Silanes to Unsaturated α-Keto Phosphonates.
abstract: A highly stereoselective vinylogous Mukaiyama Michael reaction (VMMR) leading to α-keto phosphonate-containing γ-butenolides with two stereogenic centers is described. The presented transformation is catalyzed by a combination of a commercially available C2 -symmetric bisoxazoline (BOX) ligand and a copper salt and tolerates a variety of nucleophiles and electrophiles. The stereoselectivities of the reactions are good to excellent and the products are obtained in moderate to high yields.
authors: Institute of Organic Chemistry, RWTH Aachen University, Landoltweg 1, 52056 Aachen (Germany).
authors: Anne-Dorothee
authors: AD
authors: Steinkamp
authors: Marcus
authors: M
authors: Frings
authors: Isabelle
authors: I
authors: Thomé
authors: Ingo
authors: I
authors: Schiffers
authors: Carsten
authors: C
authors: Bolm
keywords: asymmetric catalysis; bisoxazolines; copper; vinylogous Mukaiyama Michael addition; α-keto phosphonates