2004 Reactions of organo-metal compounds

Reactions of organo-metal compoundsO 0350 Stereoselective Preparation of Functionalized Unsaturated Lactones and Esters

via Functionalized Magnesium Carbenoids. — Reaction of the unsaturated esters (I) with 1 equiv. iPr-MgCl gives functionalized alkenylmagnesium carbenoids. The latter react with retention of configuration with various electrophiles to give unsaturated esters and lactones. With 2 equiv. of the magnesium reagent, a 1,2-migration reaction occurs with an unusual retention of configuration to give tetrasubstituted esters and lac-tones. — (VU, V. A.; MAREK, I.; KNOCHEL*, P.; Synthesis 2003, 12, 1797-1802; Fachbereich Chem., Ludwig-Maximilians-Univ., D-81377 Muenchen, Germany; Eng.) — C. Herrmann

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