CHEMISTRY OF CYCLOPROPYLIDENES .1. REACTION OF 7,7-DIBROMO-3-VINYLBICYCLO[4.1.0]HEPTANES WITH METHYL-LITHIUM

Reaction of anti-7,7-dibromo-3-vinylbicyclo[4.1.0]heptane (10) with LiMe, prepared from Mel and Li, leads at 25-35°C to products derived by insertion of a cyclopropylidene into the C3-H and C5-H bonds, and to insertion into the solvent ether. At -40 to -50°C, the intramolecular insertion products are replaced by exo-7-iodo-3-vinylbicyclo[4.1.0]heptane (29). Reaction of syn-7,7-dibromo-3-vinylbicyclo[4.1.0]heptane with LiMe at 25-35°C leads to a second iodide. (17) but at -40 to -50°C gives a spiro-derivative (28). The latter is converted to (17) with Lil·H 2O at 25 °C and reacts exothermally with MeOH and AcOH; it rearranges on g.l.c. or on reaction with Ag+-C6H 6, to (37) which on hydroxymercuratton leads to (38).