Nysted reagent [cyclo-dibromodi-µ-methylene(µ-tetrahydrofuran)trizinc], a commercially available gem-dimetallic compound, reacted with aldehydes affording methylenated products in the presence of BF3·OEt2, whereas methylenation of ketones proceeded in the presence of BF3·OEt2 and TiCl2.
Olefination of carbonyl compounds with gem-dizincioalkanes, bis(iodozincio)methane, 1,1-bis(iodozincio)ethane, and bis(bromozincio)methyltrimethylsilane, afforded the corresponding olefins in good to excellent yields.