ChemInform Abstract: Organocatalytic Asymmetric Wittig Reactions: Generation of Enantioenriched Axially Chiral Olefins Breaking a Symmetry Plane.

Abstract

Plane. -It is demonstrated, that the stereochemical outcome of Wittig olefinations of 4-substituted cyclohexanones can be controlled by hydrogen-bond donor catalysts such as (R,R)-TADDOL or 1,2-diaminocyclohexane derived bis-thioureas. -(GRAMIGNA, L.; DUCE, S.; FILIPPINI, G.; FOCHI, M.; FRANCHINI, M. C.; BERNARDI*, L.; Synlett 2011, 18, 2745-2749, http://dx.doi.org/10.1055/s-0031-1289516 ; Dip. Chim. Org. "A. Mangini", Univ. Bologna, I-40136 Bologna, Italy; Eng.) -Mais 13-059

Convergent Synthesis of Polysubstituted Furans via Catalytic Phosphine Mediated Multicomponent Reactions

“…The troublesome purification of the by-products [5] makes them valueless on an industrial scale [6][7][8]. Also, most well-designed phosphines, especially chiral phosphine reagents [9][10][11][12][13][14][15], are very expensive and high cost hampers their applications in asymmetric Wittig reaction [16][17][18][19][20][21][22][23][24][25]. In this context, it is highly desired to develop a catalytic version of phosphine-mediated Wittig reaction by in-situ recycling by-product phosphine oxide under the aid of a reducing agent.…”