Publications

2007
An Efficient , Facial, and General Stereoselective Synthesis of Heterosubstituted Alkylidenecyclopropanes
Masarwa, A. ; Stanger, A. ; Marek*, I. An Efficient , Facial, and General Stereoselective Synthesis of Heterosubstituted Alkylidenecyclopropanes. Angew. Chem., Int. Ed. 2007, 46, 8039-8042. Publisher's VersionAbstract

With just a nudge (in the form of silica gel, an acidic ion-exchange resin, or heating at about 40 °C), the acetate derivatives of enantiomerically enriched cyclopropenyl alcohols undergo sigmatropic rearrangement to give alkylidenecyclopropanes with high ee  values (see scheme). Similarly, the rearrangement of phosphinite derivatives at room temperature leads to phosphine oxide precursors of unusual chiral phosphine ligands. R1, R2=alkyl, aryl.

2006
Enantiomercally Pure Cyclopropeneylecarbenols as a Source of Chiral Alkylidenecyclopropane Derivatives
Simaan, S. ; Masarwa, A. ; Bertus, P. ; Marek*, I. Enantiomercally Pure Cyclopropeneylecarbenols as a Source of Chiral Alkylidenecyclopropane Derivatives. Angew. Chem., Int. Ed. 2006, 45, 3963-3965. Publisher's VersionAbstract

The straightforward approach: The copper-catalyzed carbomagnesiation reaction of chiral cyclopropenylcarbinol derivatives, obtained through kinetic resolution of secondary allylic alcohols, leads to the preparation of enantiomerically pure alkylidenecyclopropane derivatives. The reaction mechanism is composed of a syn carbometalation followed by a syn elimination reaction.

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